vector<int> twoSum(vector<int>& nums, int target) {\n vector<int> v;\n for(int i = 0 ; i < nums.size() - 1 ; i++){\n for(int j = i + 1 ; j < nums.size() ; j++){\n if(nums[i] + nums[j] == target){\n v = { i , j};\n return v;\n }\n }\n }\n return v;\n }<\/code><\/pre>\n\n\n\n\u7ed3\u679c\u6bd4\u8f83\u597d\u7684\u662f\u54c8\u5e0c\u8868\uff0c\u57fa\u672c\u539f\u7406\u5c31\u662f \u5bf9\u4e8e\u6bcf\u4e00\u4e2ax\uff0c\u6211\u4eec\u9996\u5148\u67e5\u8be2\u54c8\u5e0c\u8868\u4e2d\u662f\u5426\u5b58\u5728target – x\uff0c\u7136\u540e\u5c06x\u63d2\u5165\u5230\u54c8\u5e0c\u8868\u4e2d\uff0c\u5373\u53ef\u4fdd\u8bc1\u4e0d\u4f1a\u8ba9x\u548c\u81ea\u5df1\u5339\u914d\u3002<\/p>\n\n\n\n
tip:map\u548cunordered_map<\/p>\n\n\n\n
map\uff1a\u5e95\u5c42\u7ea2\u9ed1\u6811<\/p>\n\n\n\n
unorder_map\uff1a\u6563\u5217\u8868<\/p>\n\n\n\n![\"\"](\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\")
<\/div><\/figure>\n\n\n\nvector<int> twoSum(vector<int>& nums, int target) {\n \/\/\u521b\u5efa\u54c8\u5e0c\u8868\n unordered_map<int, int> hashtable;\n for(int i = 0 ; i < nums.size() ; i++){\n \/\/ \u8fd4\u56de\u503c\u662f\u7b2c\u4e8c\u4e2a\u6570\uff0c\u5982\u679c\u8d70\u5230\u6700\u540e\uff0c\u5219\u8bf4\u660e\u4e0d\u5b58\u5728\n auto it = hashtable.find(target - nums[i]);\n if(it != hashtable.end()){\n return {hashtable[target-nums[i]], i};\n }\n \/\/ \u4e0d\u5b58\u5728\u52a0\u5165\u6563\u5217\u8868\n hashtable[nums[i]] = i;\n }\n \/\/ c++\u8981\u6c42\u5fc5\u987b\u6700\u540e\u6709\u8fd4\u56de\n return {};\n }<\/code><\/pre>\n\n\n\n\u5b57\u6bcd\u5f02\u4f4d\u8bcd\u5206\u7ec4<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u5b57\u7b26\u4e32\u6570\u7ec4\uff0c\u8bf7\u4f60\u5c06 \u5b57\u6bcd\u5f02\u4f4d\u8bcd<\/strong> \u7ec4\u5408\u5728\u4e00\u8d77\u3002\u53ef\u4ee5\u6309\u4efb\u610f\u987a\u5e8f\u8fd4\u56de\u7ed3\u679c\u5217\u8868\u3002\u5b57\u6bcd\u5f02\u4f4d\u8bcd<\/strong> \u662f\u7531\u91cd\u65b0\u6392\u5217\u6e90\u5355\u8bcd\u7684\u6240\u6709\u5b57\u6bcd\u5f97\u5230\u7684\u4e00\u4e2a\u65b0\u5355\u8bcd\u3002<\/p>\n\n\n\n\u601d\u8def\u5927\u6982\u6709\u76f4\u63a5\u7684\u54c8\u5e0c\uff0c\u5148\u628a\u5b57\u6bcd\u90fd\u62c6\u5f00\u6309\u987a\u5e8f\u6392\u597d\u3002\u6700\u540e\u904d\u5386\u4e00\u904d\u5c31\u662f\u7b54\u6848\u3002\u91cd\u70b9\u5927\u6982\u8bb0\u4e00\u4e0b\u8bed\u6cd5\uff0c\u6bd4\u5982 string\u6392\u5e8fsort(key.begin() , key.end()); emplace_back\u7684\u7528\u6cd5\u3002<\/p>\n\n\n\n
vector<vector<string>> groupAnagrams(vector<string>& strs) {\n \/\/ key \u662f\u6392\u597d\u5e8f\u7684\uff0c\u540e\u9762\u662f\u5176\u5b83\u4e71\u5e8f\u7684\n unordered_map<string , vector<string>> mp ;\n for (auto str :strs){\n string key = str;\n sort(key.begin() , key.end());\n \/\/ \u5982\u679c key \u5df2\u7ecf\u5b58\u5728\uff0cemplace_back \u4f1a\u628a str \u6dfb\u52a0\u5230\u4e0e key \u5bf9\u5e94\u7684 vector<string> \u4e2d\u3002\n \/\/ \u5982\u679c key \u4e0d\u5b58\u5728\uff0cmp[key] \u4f1a\u81ea\u52a8\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u7a7a vector<string>\uff0c\u5e76\u5c06 str \u6dfb\u52a0\u8fdb\u53bb\u3002\n mp[key].emplace_back(str);\n }\n\n vector<vector<string>> answer;\n for(auto it = mp.begin() ; it != mp.end() ; it++){\n answer.emplace_back(it->second);\n }\n\n return answer;\n }<\/code><\/pre>\n\n\n\n\u6700\u957f\u8fde\u7eed\u5e8f\u5217<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u672a\u6392\u5e8f\u7684\u6574\u6570\u6570\u7ec4 nums<\/code> \uff0c\u627e\u51fa\u6570\u5b57\u8fde\u7eed\u7684\u6700\u957f\u5e8f\u5217\uff08\u4e0d\u8981\u6c42\u5e8f\u5217\u5143\u7d20\u5728\u539f\u6570\u7ec4\u4e2d\u8fde\u7eed\uff09\u7684\u957f\u5ea6\u3002\u8bf7\u4f60\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O(n)<\/code> <\/em>\u7684\u7b97\u6cd5\u89e3\u51b3\u6b64\u95ee\u9898\u3002<\/p>\n\n\n\n\u663e\u800c\u6613\u89c1\uff0c\u6392\u5e8fo\uff08logn\uff09\uff0c\u8fd9\u6761\u8def\u5df2\u7ecf\u5835\u6b7b\u4e86<\/p>\n\n\n\n
class Solution {\npublic:\n int longestConsecutive(vector<int>& nums) {\n int max_len = 0;\n int length = nums.size();\n unordered_map<int , int> mp;\n for(int i = 0 ; i < length ; i++){\n mp[nums[i]] = i;\n }\n\n for(int i = 0 ; i < length ; i++){\n int current_len = 0;\n int start = nums[i];\n \/\/ \u627e\u5230\u6700\u524d\u9762\n while(mp.find(start - 1) != mp.end()){\n start -= 1;\n }\n \/\/ \u4ece\u6700\u524d\u9762\u5f80\u540e\u7edf\u8ba1\uff0c\u770b\u591a\u957f\n while(mp.find(start)!= mp.end()){\n start += 1;\n current_len += 1;\n }\n max_len = current_len > max_len ? current_len : max_len;\n }\n return max_len;\n }\n};<\/code><\/pre>\n\n\n\nthen<\/p>\n\n\n\n
int longestConsecutive(vector<int>& nums) {\n int max_len = 0;\n unordered_map<int , int> mp;\n \/\/ \u5148\u628a\u6bcf\u4e00\u4e2a\u5143\u7d20\u90fd\u63d2\u5165\u6563\u5217\u8868\uff0c\u4fbf\u4e8eO(1)\u770b\u662f\u5426\u5b58\u5728\n for(int i = 0 ; i < nums.size() ; i++){\n mp[nums[i]] = i;\n }\n\n for(auto &num : nums){\n \/\/ \u904d\u5386\u4e00\u904d\uff0c\u5982\u679c\u540e\u9762\u6ca1\u5143\u7d20\u4e86\uff0c\u5219\u8bf4\u660e\u5bf9\u4e86\u3002\n \/\/ \u627e\u5230\u6700\u524d\u9762\n if(mp.find(num + 1) == mp.end()){\n int current_len = 1;\n while(mp.find(num - current_len) != mp.end()){\n current_len += 1;\n }\n max_len = current_len > max_len ? current_len : max_len;\n }\n }\n return max_len;\n }<\/code><\/pre>\n\n\n\n\u4e0a\u9762\u6211\u5176\u5b9e\u611f\u89c9\u5df2\u7ecf\u5f88\u597d\u4e86\uff0c\u4f46\u662f\u6563\u5217\u8868\u5bf9\u4e8e\u76f8\u540c\u6570\u636e\u4e0d\u4f1a\u8986\u76d6\uff0c\u800c\u662f\u94fe\u8868\u4e00\u76f4\u5f80\u540e\u8d70\u3002\u8fd9\u5c31\u5bfc\u81f4\u5f88\u591a\u6d6a\u8d39\u4e86\uff0c\u4e8b\u5b9e\u4e0a\u4e0a\u9762\u4e5f\u8d85\u65f6\u4e86\u3002\u6700\u4f73\u8fd8\u662f\u8981\u7528unorder_set<\/p>\n\n\n\n
int longestConsecutive(vector<int>& nums) {\n \/\/ \u521b\u5efa\u8fd9\u4e2aset\n unordered_set<int> num_set;\n for (const int& num : nums) {\n num_set.insert(num);\n } \n int longestStreak = 0;\n\n for (const int& num : num_set) {\n \/\/ \u5982\u679c\u662f\u6700\u540e\u4e00\u4e2a\uff0c\u4ece\u6700\u540e\u5f80\u524d\u7edf\u8ba1\n if(!num_set.count(num + 1)){\n int current_len = 1;\n while(num_set.count(num - current_len)){\n current_len ++;\n }\n if(current_len > longestStreak) longestStreak = current_len;\n }\n }\n }\n return longestStreak; \n }<\/code><\/pre>\n\n\n\n\u603b\u7ed3\uff1aset\u548cmap\u533a\u522b\u8c8c\u4f3c\u5c31\u662f\u6709\u6ca1\u6709\u952e\u503c\u5bf9\u3002\u8fd9\u91cc\u4e0d\u9700\u8981value\uff0c\u6240\u4ee5set\u597d\u4e00\u4e9b\u3002
set\u63d2\u5165\u7528insert\uff0c\u627e\u7528find\u6216\u8005count\u3002<\/p>\n\n\n\n
\u79fb\u52a8\u96f6<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u6570\u7ec4 nums<\/code>\uff0c\u7f16\u5199\u4e00\u4e2a\u51fd\u6570\u5c06\u6240\u6709 0<\/code> \u79fb\u52a8\u5230\u6570\u7ec4\u7684\u672b\u5c3e\uff0c\u540c\u65f6\u4fdd\u6301\u975e\u96f6\u5143\u7d20\u7684\u76f8\u5bf9\u987a\u5e8f\u3002<\/p>\n\n\n\nvoid moveZeroes(vector<int>& nums) {\n int zero = 0;\n int not_zero = 1;\n int length = nums.size();\n \n \/\/\u601d\u8def\u662f\uff0c\u4ece\u524d\u5f80\u540e\u627e\n while(not_zero < length){\n \/\/\u5982\u679c\u53ef\u4ee5\u4ea4\u6362\u5c31\u4ea4\u6362\n if(nums[not_zero] != 0 && nums[zero] == 0){\n int temp = nums[not_zero] ;\n nums[not_zero] = nums[zero];\n nums[zero] = temp;\n }\n \/\/\u5148\u627e\u5230\u7b2c\u4e00\u4e2a\u4e3a0\u7684\n if(nums[zero] != 0) zero++;\n \/\/\u518d\u5728\u8fd9\u4e2a\u6570\u540e\u9762\u627e\u5230\u7b2c\u4e00\u4e2a\u975e0\u7684\n if(nums[not_zero] == 0) not_zero++;\n if(zero >= not_zero) not_zero = zero;\n }\n }<\/code><\/pre>\n\n\n\n\u5b98\u65b9\u7684\u601d\u8def\u4e5f\u633a\u597d<\/p>\n\n\n\n
\u6ce8\u610f\u5230\uff1a\u5de6\u6307\u9488\u5de6\u8fb9\u5747\u4e3a\u975e\u96f6\u6570\uff1b\u53f3\u6307\u9488\u5de6\u8fb9\u76f4\u5230\u5de6\u6307\u9488\u5904\u5747\u4e3a\u96f6\u3002<\/p>\n\n\n\n
\u5927\u6982\u5c31\u662f\u53f3\u6307\u9488\u4e00\u76f4\u5411\u53f3\u8f6c\uff0c\u627e\u5230\u4e0b\u4e00\u4e2a\u4e0d\u4e3a0\u7684\u6570\u3002\u5de6\u6307\u9488\u4f1a\u57280\u5904\u505c\u4e0b\u3002<\/p>\n\n\n\n
void moveZeroes(vector<int>& nums) {\n int n = nums.size(), left = 0, right = 0;\n \/\/\u53f3\u6307\u9488\u4e0d\u65ad\u5411\u53f3\u79fb\u52a8\uff0c\u6bcf\u6b21\u53f3\u6307\u9488\u6307\u5411\u975e\u96f6\u6570\uff0c\u5219\u5c06\u5de6\u53f3\u6307\u9488\u5bf9\u5e94\u7684\u6570\u4ea4\u6362\uff0c\u540c\u65f6\u5de6\u6307\u9488\u53f3\u79fb\u3002\n while (right < n) {\n if (nums[right]) {\n swap(nums[left], nums[right]);\n left++;\n }\n right++;\n }\n }<\/code><\/pre>\n\n\n\n\u76db\u6700\u591a\u6c34\u7684\u5bb9\u5668<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u957f\u5ea6\u4e3a n<\/code> \u7684\u6574\u6570\u6570\u7ec4 height<\/code> \u3002\u6709 n<\/code> \u6761\u5782\u7ebf\uff0c\u7b2c i<\/code> \u6761\u7ebf\u7684\u4e24\u4e2a\u7aef\u70b9\u662f (i, 0)<\/code> \u548c (i, height[i])<\/code> \u3002
\u627e\u51fa\u5176\u4e2d\u7684\u4e24\u6761\u7ebf\uff0c\u4f7f\u5f97\u5b83\u4eec\u4e0e x<\/code> \u8f74\u5171\u540c\u6784\u6210\u7684\u5bb9\u5668\u53ef\u4ee5\u5bb9\u7eb3\u6700\u591a\u7684\u6c34\u3002
\u8fd4\u56de\u5bb9\u5668\u53ef\u4ee5\u50a8\u5b58\u7684\u6700\u5927\u6c34\u91cf\u3002<\/p>\n\n\n\n\u6bcf\u6b21\u90fd\u4ece\u5de6\u53f3\u6311\u4e00\u4e2a\u9ad8\u5ea6\u5c0f\u7684\uff0c\u56e0\u4e3a\u53ea\u6709\u6700\u5c0f\u7684\u90a3\u4e00\u8fb9\u53d8\u5927\uff0c\u6574\u4f53\u5bb9\u91cf\u624d\u53ef\u80fd\u53d8\u5927\u3002\u6807\u51c6\u89e3\u7b54\u8c8c\u4f3c\u6bcf\u6b21\u90fd\u4f1a\u8ba1\u7b97\u5bb9\u91cf\uff0c\u4e0d\u8fc7\u6211\u7684\u89e3\u6cd5\u867d\u7136\u4e0d\u7528\u8fd9\u6837\u5374\u5f88\u957f\u3002\u7efc\u5408\u8003\u8651\u5c31\u8fd9\u6837\u5427\u3002<\/p>\n\n\n\n
int maxArea(vector<int>& height) {\n int l = 0, r = height.size() - 1;\n int ans = 0;\n while (l < r) {\n int area = min(height[l], height[r]) * (r - l);\n ans = max(ans, area);\n if (height[l] <= height[r]) {\n ++l;\n }\n else {\n --r;\n }\n }\n return ans;<\/code><\/pre>\n\n\n\n\u4e09\u6570\u4e4b\u548c<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums \uff0c\u5224\u65ad\u662f\u5426\u5b58\u5728\u4e09\u5143\u7ec4 [nums[i], nums[j], nums[k]] \u6ee1\u8db3 i != j\u3001i != k \u4e14 j != k \uff0c\u540c\u65f6\u8fd8\u6ee1\u8db3 nums[i] + nums[j] + nums[k] == 0 \u3002\u8bf7\u4f60\u8fd4\u56de\u6240\u6709\u548c\u4e3a 0 \u4e14\u4e0d\u91cd\u590d\u7684\u4e09\u5143\u7ec4\u3002<\/p>\n\n\n\n
\u904d\u5386O(N3<\/sup>)\uff0c\u5f88\u53ef\u60dc\u5c31\u8d85\u65f6\u4e86<\/p>\n\n\n\nvector<vector<int>> threeSum(vector<int>& nums) {\n vector<vector<int>> ret;\n set<vector<int>> result;\n int length = nums.size();\n\n for(int i = 0 ; i < length ; i++){\n for(int j = i + 1 ; j < length ; j++){\n for(int k = j + 1 ; k < length ; k++){\n if (nums[i] + nums[j] + nums[k] == 0)\n {\n vector<int> temp = {nums[i] , nums[j] , nums[k]};\n sort(temp.begin() , temp.end());\n result.insert(temp);\n }\n }\n }\n }\n for(auto key : result){\n ret.push_back(key);\n }\n return ret;\n }<\/code><\/pre>\n\n\n\n\u53cc\u6307\u9488\u904d\u5386\uff0c\u5f88\u5de7\u5999<\/p>\n\n\n\n
class Solution {\npublic:\n vector<vector<int>> threeSum(vector<int>& nums) {\n int n = nums.size();\n vector<vector<int>> ret;\n sort(nums.begin() , nums.end());\n\n \/\/ \u6700\u5de6\u8fb9\u6307\u9488\n for(int frist = 0 ; frist < n ; frist++){\n \/\/ \u627e\u5230\u4e0d\u4e00\u6837\u7684\u503c\n if(frist > 0 && nums[frist -1] == nums[frist])\n continue;\n \n \/\/ third\u521d\u59cb\u662f\u6700\u5927\u7684\u503c\n int third = n -1;\n\n \/\/ \u5728\u4e2d\u95f4\u904d\u5386\n for(int second = frist + 1 ; second < third ; second++){\n if(second > frist + 1 && nums[second] == nums[second - 1] )\n continue;\n \n \/\/\u6700\u5c0f\u7684\u4e24\u4e2a\u76f8\u52a0\u90fd\u6bd4\u6700\u5927\u503c\u5927\uff0c\u90a3\u9700\u8981\u6700\u5927\u503c\u53d8\u5c0f\n while(second < third && nums[second] + nums[third] + nums[frist] > 0){\n third --;\n }\n\n \/\/\u91cd\u5408\uff0c\u53ef\u4ee5\u9000\u51fa\u4e86\n if(second == third) break;\n if(nums[second] + nums[third] + nums[frist] == 0){\n ret.push_back({nums[frist], nums[second], nums[third]});\n }\n }\n }\n return ret;\n }\n};<\/code><\/pre>\n\n\n\n\u63a5\u96e8\u6c34<\/h3>\n\n\n\n
\u7ed9\u5b9a n<\/code> \u4e2a\u975e\u8d1f\u6574\u6570\u8868\u793a\u6bcf\u4e2a\u5bbd\u5ea6\u4e3a 1<\/code> \u7684\u67f1\u5b50\u7684\u9ad8\u5ea6\u56fe\uff0c\u8ba1\u7b97\u6309\u6b64\u6392\u5217\u7684\u67f1\u5b50\uff0c\u4e0b\u96e8\u4e4b\u540e\u80fd\u63a5\u591a\u5c11\u96e8\u6c34\u3002<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n\u521d\u770b\u975e\u5e38\u9006\u5929\u96be\uff0c\u4f46\u662f\u770b\u4e86\u89e3\u6790\u597d\u50cf\u5c31\u53c8\u7b80\u5355\u4e86<\/p>\n\n\n\n
\u4e00\u662f\u52a8\u6001\u89c4\u5212\uff0c\u4e8c\u662f\u4e0b\u9762\u7684<\/p>\n\n\n\n
\n- \u4f7f\u7528height[left]\u548cheight[right]\u7684\u503c\u66f4\u65b0leftMax\u548crightMax\u7684\u503c\uff1b<\/li>\n\n\n\n
- \u5982\u679cheight[left]<height[right]\uff0c\u5219\u5fc5\u6709leftMax<rightMax\uff0c\u4e0b\u6807left\u5904\u80fd\u63a5\u7684\u96e8\u6c34\u91cf\u7b49\u4e8eleftMax\u2212height[left]\uff0c\u5c06\u4e0b\u6807left\u5904\u80fd\u63a5\u7684\u96e8\u6c34\u91cf\u52a0\u5230\u80fd\u63a5\u7684\u96e8\u6c34\u603b\u91cf\uff0c\u7136\u540e\u5c06left\u52a01\uff08\u5373\u5411\u53f3\u79fb\u52a8\u4e00\u4f4d\uff09\uff1b<\/li>\n\n\n\n
- \u5982\u679cheight[left]\u2265height[right]\uff0c\u5219\u5fc5\u6709leftMax\u2265rightMax\uff0c\u4e0b\u6807right\u5904\u80fd\u63a5\u7684\u96e8\u6c34\u91cf\u7b49\u4e8erightMax\u2212height[right]\uff0c\u5c06\u4e0b\u6807right\u5904\u80fd\u63a5\u7684\u96e8\u6c34\u91cf\u52a0\u5230\u80fd\u63a5\u7684\u96e8\u6c34\u603b\u91cf\uff0c\u7136\u540e\u5c06right\u51cf1\uff08\u5373\u5411\u5de6\u79fb\u52a8\u4e00\u4f4d\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
int trap(vector<int>& height) {\n int ans = 0;\n int left = 0 , right = height.size() - 1;\n int left_max = 0 , right_max = 0;\n\n while(left < right){\n \/\/\u53d6\u5f53\u524d\u6700\u5927\n left_max = max(left_max , height[left]);\n right_max = max(right_max , height[right]);\n \n \/\/\u5982\u679c\u5de6\u8fb9\u9ad8\u5ea6\u5c0f\u4e8e\u53f3\u8fb9\uff0c\u8868\u793a\u5de6\u8fb9\u4e00\u5b9a\u53ef\u4ee5\u90fd\u4e0a\n if(height[left] < height[right]){\n ans += left_max - height[left];\n ++left;\n } else {\n ans += right_max - height[right];\n -- right;\n }\n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u6709\u4e00\u4e2a\u66f4\u597d\u7406\u89e3\u7684<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n\u548c\u4e3a K \u7684\u5b50\u6570\u7ec4<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums \u548c\u4e00\u4e2a\u6574\u6570 k \uff0c\u8bf7\u4f60\u7edf\u8ba1\u5e76\u8fd4\u56de \u8be5\u6570\u7ec4\u4e2d\u548c\u4e3a k \u7684\u5b50\u6570\u7ec4\u7684\u4e2a\u6570 \u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u5355\u7eaf\u7684\u6392\u8868\uff0cO\uff08n2<\/sup>\uff09<\/p>\n\n\n\nint subarraySum(vector<int>& nums, int k) {\n \n int sum = 0;\n int n = nums.size();\n \n for(int i = 0 ; i < n ; i++){\n int current = 0;\n for(int j = i ; j < n ; j++){\n current += nums[j];\n if(current == k) sum ++;\n }\n }\n return sum;\n }<\/code><\/pre>\n\n\n\n\u7ed3\u679c\u7b54\u6848\u6709\u4e2a\u751c\u83dc\u60f3\u6cd5\uff0c\u5047\u8bbe\u7528a[i]\u8868\u793a\u4ece0\u52a0\u5230i\uff0c\u90a3\u6211\u8981i,j\u4e4b\u95f4\u53ea\u9700\u8981a[j] – a[i-1]\u3002\u90a3\u8fd9\u6837\uff0c\u6211\u8981\u6c42\u4e00\u4e2a\u533a\u95f4[j,i]\u7684\u548c\u4e3atarget\uff0c\u5219\u4e3aa[i] – a[j] = target\uff0c\u90a3\u5bf9\u4e8e\u4efb\u610f\u4e00\u4e2aa[i]\uff0c\u6211\u4eec\u53ea\u9700\u8981\u5bf9\u5b83\u524d\u9762\u7684\u6570\u5b57\u5224\u65ad\uff0c\u662f\u5426\u6709\u7b49\u4e8ea[i]-target\u5373\u53ef\uff0c\u5982\u679co1\u53ef\u4ee5\u5224\u65ad\uff0c\u90a3\u4e48\u6700\u7ec8\u7b97\u6cd5\u590d\u6742\u5ea6\u5c31\u662fO(n)<\/p>\n\n\n\n
\u4e16\u754c\u4e0a\u60f3\u51fa\u8fd9\u4e48\u5de7\u5999\u7b97\u6cd5\u7684\u4eba\u90fd\u662f\u751c\u83dc\u5417\uff1f<\/p>\n\n\n\n
int subarraySum(vector<int>& nums, int k) {\n unordered_map<int , int> mp;\n \/\/\u4fdd\u8bc1\u6bd4\u5982\u8bf4\u81ea\u76f8\u7b49\u60c5\u51b5\u4e0b\uff0c\u53ef\u4ee5\u7edf\u8ba1\u5230\n mp[0] = 1;\n int sum = 0;\n int count = 0;\n for(int i = 0 ; i < nums.size() ; i++){\n sum += nums[i];\n if(mp.find(sum - k) != mp.end()){\n count += mp[sum - k];\n }\n mp[sum]++;\n }\n return count;\n \n }<\/code><\/pre>\n\n\n\n\u65e0\u91cd\u590d\u5b57\u7b26\u7684\u6700\u957f\u5b50\u4e32<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u5b57\u7b26\u4e32 s<\/code> \uff0c\u8bf7\u4f60\u627e\u51fa\u5176\u4e2d\u4e0d\u542b\u6709\u91cd\u590d\u5b57\u7b26\u7684 \u6700\u957f \u5b50\u4e32 <\/strong>\u7684\u957f\u5ea6\u3002<\/p>\n\n\n\n\u65e9\u4e0a\u53ef\u80fd\u72b6\u6001\u597d\uff1f\u4e00\u4e0b\u5c31\u505a\u51fa\u6765\u4e86
\u53f3\u6307\u9488\u6bcf\u6b21\u90fd\u662f\u65b0\u52a0\u5165\u7684\u5143\u7d20\uff0c\u5982\u679c\u5df2\u7ecf\u5b58\u5728\uff0c\u90a3\u5de6\u6307\u9488\u5c31\u5220\u6389\u81ea\u5df1\u7684\u5411\u53f3\u79fb\u52a8<\/p>\n\n\n\n
int lengthOfLongestSubstring(string s) {\n unordered_set<char> st;\n int n = s.length();\n int left= 0 , right = 0;\n int max_length = 0;\n int current_length = 0;\n while(right < n ){\n \/\/\u6ca1\u627e\u5230\n if(st.count(s[right]) == 0){\n st.insert(s[right]);\n current_length ++;\n right++;\n }\n \/\/\u627e\u5230\u4e86\n else{\n st.erase(s[left]);\n left++;\n current_length --;\n }\n max_length = current_length > max_length ? current_length : max_length;\n }\n return max_length;\n }<\/code><\/pre>\n\n\n\n\u627e\u5230\u5b57\u7b26\u4e32\u4e2d\u6240\u6709\u5b57\u6bcd\u5f02\u4f4d\u8bcd<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e24\u4e2a\u5b57\u7b26\u4e32 s<\/code> \u548c p<\/code>\uff0c\u627e\u5230 s<\/code> <\/strong>\u4e2d\u6240\u6709 p<\/code> <\/strong>\u7684 \u5f02\u4f4d\u8bcd <\/strong>\u7684\u5b50\u4e32\uff0c\u8fd4\u56de\u8fd9\u4e9b\u5b50\u4e32\u7684\u8d77\u59cb\u7d22\u5f15\u3002\u4e0d\u8003\u8651\u7b54\u6848\u8f93\u51fa\u7684\u987a\u5e8f\u3002<\/p>\n\n\n\n\u592a\u4f4e\u6548\u4e86\uff0c\u76f4\u63a5timeout\u3002\u590d\u6742\u5ea6\u662fo(nNlogN)\u3002\u770b\u6765\u5fc5\u7136\u662fp\u540e\u7eed\u7684N\u592a\u5927\u4e86\u3002<\/p>\n\n\n\n
vector<int> findAnagrams(string s, string p) {\n vector<int> ans;\n int n_s = s.length() , n_p = p.length();\n sort(p.begin() , p.end());\n int left = 0 ;\n while(left + n_p - 1 < n_s){\n string subStr = s.substr(left , n_p);\n sort(subStr.begin() , subStr.end());\n if(p == subStr){\n ans.push_back(left);\n }\n left++;\n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u60f3\u51fa\u6765\u4e86O\uff08n\uff09\u7684\uff0c\u89c9\u5f97\u975e\u5e38\u591f\u7528\u3002\u6ce8\u610f\u7684\u70b9\u662f\uff0c\u867d\u7136unordered_map<char , int>\u5728\u521d\u59cb\u5316\u65f6\u5019\uff0c\u5982\u679cvalue\u6ca1\u6709\uff0c\u90a3\u9ed8\u8ba4\u662f0\uff0c\u4f46\u662f\u4e8c\u8005\u6bd4\u8f83\u65f6\u5019\u5e76\u4e0d\u4f1a\u76f8\u7b49\u3002
\u5269\u4e0b\u7684\u5c31\u662f\u6ed1\u52a8\u6bd4\u8f83\uff0c\u52a0\u4e00\u4e2a\u51cf\u4e00\u4e2a<\/p>\n\n\n\n
vector<int> findAnagrams(string s, string p) {\n vector<int> ans;\n int n_s = s.length() , n_p = p.length();\n unordered_map<char , int> mp;\n unordered_map<char , int> ans_mp;\n for(int i = 0 ; i < 26 ; i++){\n mp['a'+ i] = 0;\n ans_mp['a'+ i] = 0;\n }\n\n for(int i = 0 ; i < n_p ; i++){\n mp[s[i]]++;\n ans_mp[p[i]]++;\n }\n for(int i = 0 ; i + n_p - 1 < n_s ; i++){\n if(mp == ans_mp){\n ans.push_back(i);\n }\n mp[ s[i] ]--;\n mp[ s[i + n_p] ]++;\n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u6ed1\u52a8\u7a97\u53e3\u6700\u5927\u503c<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums<\/code>\uff0c\u6709\u4e00\u4e2a\u5927\u5c0f\u4e3a k<\/code> <\/em>\u7684\u6ed1\u52a8\u7a97\u53e3\u4ece\u6570\u7ec4\u7684\u6700\u5de6\u4fa7\u79fb\u52a8\u5230\u6570\u7ec4\u7684\u6700\u53f3\u4fa7\u3002\u4f60\u53ea\u53ef\u4ee5\u770b\u5230\u5728\u6ed1\u52a8\u7a97\u53e3\u5185\u7684 k<\/code> \u4e2a\u6570\u5b57\u3002\u6ed1\u52a8\u7a97\u53e3\u6bcf\u6b21\u53ea\u5411\u53f3\u79fb\u52a8\u4e00\u4f4d\u3002<\/p>\n\n\n\n\u8fd4\u56de \u6ed1\u52a8\u7a97\u53e3\u4e2d\u7684\u6700\u5927\u503c <\/em>\u3002<\/p>\n\n\n\n\u76f4\u63a5\u60f3\u5230\u7684\u65b9\u6cd5\u662f\u4f18\u5148\u7ea7\u961f\u5217\u3002\u8fd9\u6837\u6bcf\u6b21logN\uff0c\u6574\u4f53\u5c31\u662fnlogN\u3002\u57fa\u4e8e\u7ea2\u9ed1\u6811\u5dee\u4e0d\u591a<\/p>\n\n\n\n
vector<int> maxSlidingWindow(vector<int>& nums, int k) {\n \/\/ deque\u4ece\u524d\u540e\u90fd\u53ef\u4ee5pop\n deque<int> q;\n int n = nums.size();\n\n \/\/ \u5148\u662f\u5bf9\u6700\u524d\u9762K\u4e2a\uff0c\u4e14\u9898\u76ee\u63d0\u5230 k < n\u4e86\n for(int i = 0 ; i < k ; i++){\n \/\/ \u6b64\u65f6q\u5185\u90e8\u662f\u964d\u5e8f\u6392\u5217\uff0c\u5982\u679c\u540e\u9762\u7684\u6bd4\u4ed6\u5927\uff0c\u90a3\u8bf4\u660e\u524d\u9762\u7684\u90fd\u6ca1\u7528\u4e86\n while(!q.empty() && nums[i] > nums[q.back()]){\n q.pop_back();\n }\n q.push_back(i);\n }\n\n \/\/\u6b64\u65f6\uff0c\u7b2c\u4e00\u4e2a\u6570\u5b57\u5c31\u662f\u524d\u9762\u6700\u5927\u7684\n vector<int> ans = {nums[q.front()]};\n for(int i = k ; i < n ; i++){\n \/\/\u8fd8\u662f\u4e00\u6837\uff0c\u5982\u679c\u5927\u4e86\u5c31\u8e22\u51fa\u53bb\n while(!q.empty() && nums[i] > nums[q.back()]){\n q.pop_back();\n }\n \/\/\u6781\u7aef\u60c5\u51b5\u53ef\u80fd\u6709k+1\u4e2a\u6570\uff0c\u4f46\u65e0\u6240\u8c13\uff0c\u9a6c\u4e0a\u5c31\u8e22\u4eba\n q.push_back(i);\n\n if(q.front() <= i - k){\n q.pop_front();\n }\n ans.push_back(nums[q.front()]);\n }\n return ans;<\/code><\/pre>\n\n\n\n\u6700\u5c0f\u8986\u76d6\u5b50\u4e32<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u5b57\u7b26\u4e32 s<\/code> \u3001\u4e00\u4e2a\u5b57\u7b26\u4e32 t<\/code> \u3002\u8fd4\u56de s<\/code> \u4e2d\u6db5\u76d6 t<\/code> \u6240\u6709\u5b57\u7b26\u7684\u6700\u5c0f\u5b50\u4e32\u3002\u5982\u679c s<\/code> \u4e2d\u4e0d\u5b58\u5728\u6db5\u76d6 t<\/code> \u6240\u6709\u5b57\u7b26\u7684\u5b50\u4e32\uff0c\u5219\u8fd4\u56de\u7a7a\u5b57\u7b26\u4e32 \"\"<\/code> \u3002<\/p>\n\n\n\n\u6838\u5fc3\u601d\u60f3\uff1a\u53f3\u8fb9r\u4e00\u76f4\u5f80\u53f3\u8d70\uff0c\u68c0\u67e5\u533a\u95f4\u5185\u662f\u5426\u6ee1\u8db3\u8981\u6c42\u3002\u5982\u679c\u6ee1\u8db3\u8981\u6c42\u5c31\u7f29\u5de6\u8fb9\uff0c\u6700\u7ec8\u53d6\u5230\u4e00\u4e2a\u6bd4\u8f83\u597d\u7684\u7ed3\u679c\u3002<\/p>\n\n\n\n
class Solution {\npublic:\n unordered_map<char , int> m_s;\n int check(){\n for(auto p : m_s){\n if(p.second < 0)\n return 0;\n }\n return 1;\n }\n\n string minWindow(string s, string t) {\n \n int n_s = s.length() , n_t = t.length();\n\n \/\/ \u8bbe\u5b9a\u4e3a\u8d1f\u6570\uff0c\u53ea\u6709\u5168\u6b63\u624d\u8bf4\u660e\u6ee1\u8db3\u8981\u6c42\n for(int i = 0 ; i < n_t ; i++){\n m_s[t[i]] --;\n }\n\n int l = 0 , r = 0;\n int len = INT_MAX, ansL = -1;\n while(r < n_s){\n \/\/\u5bf9\u5e94\u7684\u8868\u91cc+1\uff0c\u5411\u53f3\u79fb\u52a8\n m_s[s[r]]++;\n \n \/\/\u5f53\u6ee1\u8db3\u8981\u6c42\uff0c\u5f00\u59cb\u7f29\u5de6\u8fb9\n while(check()){\n \/\/\u6bd4\u6700\u5927\u7684\u5c0f\uff0c\u66f4\u65b0\u5de6\u8fb9\u7b54\u6848\n if(r - l + 1 < len){\n len = r - l + 1;\n ansL = l;\n }\n m_s[s[l]]--;\n l++;\n }\n r++;\n }\n\n return ansL == -1 ? \"\" : s.substr(ansL , len);\n }\n};<\/code><\/pre>\n\n\n\n\u6700\u5927\u5b50\u6570\u7ec4\u548c<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums<\/code> \uff0c\u8bf7\u4f60\u627e\u51fa\u4e00\u4e2a\u5177\u6709\u6700\u5927\u548c\u7684\u8fde\u7eed\u5b50\u6570\u7ec4\uff08\u5b50\u6570\u7ec4\u6700\u5c11\u5305\u542b\u4e00\u4e2a\u5143\u7d20\uff09\uff0c\u8fd4\u56de\u5176\u6700\u5927\u548c\u3002<\/p>\n\n\n\n\u5b50\u6570\u7ec4<\/strong>\u662f\u6570\u7ec4\u4e2d\u7684\u4e00\u4e2a\u8fde\u7eed\u90e8\u5206\u3002<\/p>\n\n\n\nint maxSubArray(vector<int>& nums) {\n int pre = 0 , max_ans = nums[0];\n for(int i = 0 ; i < nums.size() ; i++){\n \/\/ \u5f53\u524d\u6570\u6700\u5927\u503c\uff0c\u6bd4\u8f83\u524d\u9762\u7684\u6570\u52a0\u4e0a\u81ea\u5df1\u548c\u5f53\u524d\u6570\u6bd4\u8f83\n \/\/ \u5982\u679c\u4ece\u81ea\u5df1\u8fd9\u91cc\u5f00\u59cb\u597d\u90a3\u524d\u9762\u7684\u80af\u5b9a\u6ca1\u7528\u4e86\n pre = max(pre + nums[i] , nums[i]);\n max_ans = max(max_ans , pre);\n }\n return max_ans;\n }<\/code><\/pre>\n\n\n\n\u5408\u5e76\u533a\u95f4<\/h3>\n\n\n\n
\u4ee5\u6570\u7ec4 intervals<\/code> \u8868\u793a\u82e5\u5e72\u4e2a\u533a\u95f4\u7684\u96c6\u5408\uff0c\u5176\u4e2d\u5355\u4e2a\u533a\u95f4\u4e3a intervals[i] = [starti<\/sub>, endi<\/sub>]<\/code> \u3002\u8bf7\u4f60\u5408\u5e76\u6240\u6709\u91cd\u53e0\u7684\u533a\u95f4\uff0c\u5e76\u8fd4\u56de \u4e00\u4e2a\u4e0d\u91cd\u53e0\u7684\u533a\u95f4\u6570\u7ec4\uff0c\u8be5\u6570\u7ec4\u9700\u6070\u597d\u8986\u76d6\u8f93\u5165\u4e2d\u7684\u6240\u6709\u533a\u95f4<\/em> \u3002<\/p>\n\n\n\n\u601d\u8def\u5927\u6982\u5c31\u662f\u5148\u6392\u5e8f\uff0c\u6309\u7167\u7b2c\u4e00\u4e2a\u6570\u6392\u3002\u62cd\u597d\u540e\u4ece\u524d\u5f80\u540e\u904d\u5386\u5904\u7406\u3002
\u6ca1\u60f3\u5230\u7684\u70b9\u662fsort(intervals.begin(), intervals.end());\u5c45\u7136\u53ef\u4ee5\u76f4\u63a5\u5bf9\u4e8c\u7ef4\u6570\u7ec4\u6392\u5e8f\uff0c\u4f9d\u636e\u8fd8\u662f\u6839\u636e\u7b2c\u4e00\u4e2a\u6570\u3002<\/p>\n\n\n\n
vector<vector<int>> merge(vector<vector<int>>& intervals) {\n if(intervals.size() == 0) return{};\n\n sort(intervals.begin(), intervals.end());\n int n = intervals.size();\n\n vector<vector<int>> ans;\n int l = intervals[0][0] , r = intervals[0][1];\n for(int i = 1 ; i < n ; i++){\n \/\/\u5de6\u8fb9\u90fd\u8d85\u51fa\u8fb9\u754c\uff0c\u5219\u53ef\u4ee5\u628a\u4e4b\u524d\u90a3\u4e2a\u52a0\u8fdb\u53bb\u4e86\uff0c\u5e76\u5f00\u59cb\u65b0\u4e00\u8f6e\u5faa\u73af\n if(intervals[i][0] > r){\n ans.push_back({l,r});\n l = intervals[i][0];\n r = intervals[i][1];\n }\n else{\n \/\/\u6269\u5bbd\u5230\u76ee\u524d\u53ef\u8fbe\u6700\u8fdc\n if(intervals[i][1] > r){\n r = intervals[i][1];\n }\n }\n }\n \/\/\u6700\u540e\u4e00\u5bf9\u6ca1\u6709\u52a0\u4e0a\uff0c\u8865\u5168\n ans.push_back({l,r});\n return ans;\n }<\/code><\/pre>\n\n\n\n\u8f6e\u8f6c\u6570\u7ec4<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums<\/code>\uff0c\u5c06\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\u5411\u53f3\u8f6e\u8f6c k<\/code> <\/em>\u4e2a\u4f4d\u7f6e\uff0c\u5176\u4e2d k<\/code> <\/em>\u662f\u975e\u8d1f\u6570\u3002<\/p>\n\n\n\n\u7ecf\u5178\u4e09\u6b21reverse\uff0c\u591a\u60f3\u4e00\u4e0b\u5c31\u611f\u53d7\u5230\u5de7\u5999\u4e86<\/p>\n\n\n\n
class Solution {\npublic:\n void reverse(vector<int>& nums , int start , int end){\n while(start < end){\n swap(nums[start] , nums[end]);\n start++;\n end--;\n }\n }\n void rotate(vector<int>& nums, int k) {\n int n = nums.size();\n k %= n;\n reverse(nums , 0 , n - 1);\n reverse(nums , 0 , k - 1);\n reverse(nums , k , n - 1);\n }\n};<\/code><\/pre>\n\n\n\n\u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums<\/code>\uff0c\u8fd4\u56de \u6570\u7ec4 answer<\/code> \uff0c\u5176\u4e2d answer[i]<\/code> \u7b49\u4e8e nums<\/code> \u4e2d\u9664 nums[i]<\/code> \u4e4b\u5916\u5176\u4f59\u5404\u5143\u7d20\u7684\u4e58\u79ef \u3002<\/p>\n\n\n\n\u9898\u76ee\u6570\u636e \u4fdd\u8bc1<\/strong> \u6570\u7ec4 nums<\/code>\u4e4b\u4e2d\u4efb\u610f\u5143\u7d20\u7684\u5168\u90e8\u524d\u7f00\u5143\u7d20\u548c\u540e\u7f00\u7684\u4e58\u79ef\u90fd\u5728 32 \u4f4d<\/strong> \u6574\u6570\u8303\u56f4\u5185\u3002<\/p>\n\n\n\n\u8bf7 \u4e0d\u8981\u4f7f\u7528\u9664\u6cd5\uff0c<\/strong>\u4e14\u5728 O(n)<\/code> \u65f6\u95f4\u590d\u6742\u5ea6\u5185\u5b8c\u6210\u6b64\u9898\u3002<\/p>\n\n\n\n\u4e00\u4e2aclassic\u601d\u8def\uff0c\u4e24\u4e2a\u6570\u7ec4\uff0c\u4e00\u4e2a\u8bb0\u5f55\u6b63\u5411\u4e58\u79ef\uff0c\u53e6\u4e00\u4e2a\u8bb0\u5f55\u53cd\u5411\u4e58\u79ef\u3002\u6700\u7ec8\u4e8c\u8005\u76f8\u7ed3\u5408\uff0c\u5f97\u5230\u60f3\u8981\u7684\u7b54\u6848<\/p>\n\n\n\n
vector<int> productExceptSelf(vector<int>& nums) {\n int n = nums.size();\n vector<int> L(n , 0);\n vector<int> R(n , 0);\n\n L[0] = nums[0];\n R[n - 1] = nums[n - 1];\n for(int i = 1 ; i < n ; i++){\n L[i] = L[i -1] * nums[i];\n R[n - i - 1] = R [n - i] * nums[n - i - 1];\n }\n\n vector<int> ans(n , 0);\n ans[0] = R[1];\n ans[n - 1] = L[n-2];\n for(int i = 1 ; i < n - 1 ; i++){\n ans[i] = L[i - 1] * R[i + 1];\n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u7ed3\u679c\u901f\u5ea6\u8fd8\u4e0d\u662f\u5f88\u5feb\u3002\u770b\u7684\u6700\u4f73\u7684\u601d\u8def\u662f\uff0c\u5176\u5b9e\u53ea\u7528\u4e00\u4e2a\u6570\u7ec4\u5c31\u591f\u4e86\u3002\u5f00\u59cb\u5168\u90e8\u8bbe\u7f6e\u4e3a1\uff0c\u5de6\u53f3\u53cc\u6307\u9488\u8d70\u3002\u5de6\u6307\u9488\u5c31\u8bb0\u5f55\u5230\u8fd9\u4e2a\u4f4d\u7f6e\u5de6\u8fb9\u4e58\u79ef\uff0c\u4e58\u597d\u540e\u653e\u5728\u8fd9\u91cc\u3002\u53f3\u8fb9\u540c\u7406\u3002\u8fd9\u6837\u4e00\u6b21\u5c31\u5168\u90e8\u8dd1\u5b8c\u4e86\u3002\u751c\u83dc\u8fd8\u662f\u592a\u65e0\u6cd5\u6218\u80dc\u4e86\u3002<\/p>\n\n\n\n
vector<int> productExceptSelf(vector<int>& nums) {\n int n = nums.size();\n vector<int> ans(n , 1);\n int L = 1 , R = 1;\n for(int i = 1 ; i < n ; i++){\n L *= nums[i-1];\n ans[i] *= L;\n R *= nums[n - i];\n ans[n-i-1] *= R; \n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u53ea\u51fa\u73b0\u4e00\u6b21\u7684\u6570\u5b57<\/p>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a \u975e\u7a7a \u6574\u6570\u6570\u7ec4 nums \uff0c\u9664\u4e86\u67d0\u4e2a\u5143\u7d20\u53ea\u51fa\u73b0\u4e00\u6b21\u4ee5\u5916\uff0c\u5176\u4f59\u6bcf\u4e2a\u5143\u7d20\u5747\u51fa\u73b0\u4e24\u6b21\u3002\u627e\u51fa\u90a3\u4e2a\u53ea\u51fa\u73b0\u4e86\u4e00\u6b21\u7684\u5143\u7d20\u3002<\/p>\n\n\n\n
\u4f60\u5fc5\u987b\u8bbe\u8ba1\u5e76\u5b9e\u73b0\u7ebf\u6027\u65f6\u95f4\u590d\u6742\u5ea6\u7684\u7b97\u6cd5\u6765\u89e3\u51b3\u6b64\u95ee\u9898\uff0c\u4e14\u8be5\u7b97\u6cd5\u53ea\u4f7f\u7528\u5e38\u91cf\u989d\u5916\u7a7a\u95f4\u3002<\/p>\n\n\n\n
\u975e\u5e38\u7ecf\u5178\u7684\u8111\u7b4b\u6025\u8f6c\u5f2f\u3002\u5f00\u59cb\u60f3\u5230\u7684\u54c8\u5e0c\u8868\uff0c\u7ed3\u679c\u5c31\u6d6a\u8d39O\uff08n\uff09\u7a7a\u95f4\u4e0d\u53ef\u4ee5\u3002\u3002\u7ed3\u679c\u76f4\u63a5\u5168\u90e8\u5f02\u6216\u5c31\u5b8c\u4e8b\u4e86,,,\u8fd8\u662f\u633a\u65e0\u8bed\u7684<\/p>\n\n\n\n
\u7f3a\u5931\u7684\u7b2c\u4e00\u4e2a\u6b63\u6570<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a\u672a\u6392\u5e8f\u7684\u6574\u6570\u6570\u7ec4 nums<\/code> \uff0c\u8bf7\u4f60\u627e\u51fa\u5176\u4e2d\u6ca1\u6709\u51fa\u73b0\u7684\u6700\u5c0f\u7684\u6b63\u6574\u6570\u3002\u8bf7\u4f60\u5b9e\u73b0\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O(n)<\/code> \u5e76\u4e14\u53ea\u4f7f\u7528\u5e38\u6570\u7ea7\u522b\u989d\u5916\u7a7a\u95f4\u7684\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n\n\n\nint firstMissingPositive(vector<int>& nums) {\n \/\/ \u8fd9\u79cd\u4e5f\u662f\u795e\u4eba\u9898\u76ee\u4e86\uff0c\u6216\u8005\u8bf4\u7edd\u5927\u90e8\u5206\u56f0\u96be\u9898\u76ee\n \/\/ \u65e0\u5f02\u4e8e\u4e00\u4e2a\u8111\u7b4b\u6025\u8f6c\u5f2f\u3002\u770b\u8fc7\u5c31\u4f1a\uff0c\u6ca1\u770b\u8fc7\u5c31\u5f88\u53ef\u80fd\u60f3\u4e0d\u51fa\u6765\u3002\n \/\/ \u5f53\u4f60\u8d39\u52b2\u5fc3\u601d\u60f3\u5230\u4e00\u4e2a\u89e3\uff0c\u5374\u53d1\u73b0\u590d\u6742\u5ea6\u65e9\u5c31\u9650\u5236\u6b7b\u4e86\uff0c\u63a5\u7740\u770b\u5230\u7b54\u6848\u53ea\u80fd\u65e0\u8bed\u7684\u7b11\u4e86\n\n int n = nums.size();\n \/\/\u5bf9\u4e8e\u8d1f\u6570\u548c0\uff0c\u5168\u90e8\u8ba9\u5b83\u8d85\u8fc7\u6570\u7ec4\u5927\u5c0f\uff0c\u8fd9\u6837\u4e0d\u4f1a\u5f71\u54cd\u6b63\u5e38\u503c\n for(int i = 0 ; i < n ; i++){\n if(nums[i] <= 0) nums[i] = n + 1;\n }\n\n \/\/ \u90a3\u4e48\u5269\u4e0b\u7684\u5c31\u5168\u662f\u6b63\u6570\u4e86\uff0c\u6b64\u65f6\u5bf9\u4e8e<= n\u7684\u90e8\u5206\uff0c\u53bb\u6570\u7ec4\u627e\u5bf9\u5e94\u4f4d\u7f6e\uff0c\u8bbe\u7f6e\u4e3a\u8d1f\u6570(\u76f4\u63a5*-1\u90a3\u4e48\u5076\u6570\u6b21\u4f1a\u51fa\u95ee\u9898)\n for(int i = 0 ; i < n ;i++){\n if(abs(nums[i]) <= n) nums[abs(nums[i]) - 1] = -abs(nums[abs(nums[i]) - 1]);\n }\n \/\/ \u627e\u5230\u7b2c\u4e00\u4e2a\u6b63\u6570\u5373\u53ef\uff0c\u6ca1\u6709\u88ab\u6620\u5c04\u8fc7\u3002\n for(int i = 0 ; i < n ; i++){\n if(nums[i] > 0 ) return i + 1; \n }\n return n + 1;\n }<\/code><\/pre>\n\n\n\n\u77e9\u9635\u7f6e\u96f6<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a m<\/em> x n<\/em><\/code> \u7684\u77e9\u9635\uff0c\u5982\u679c\u4e00\u4e2a\u5143\u7d20\u4e3a 0 <\/strong>\uff0c\u5219\u5c06\u5176\u6240\u5728\u884c\u548c\u5217\u7684\u6240\u6709\u5143\u7d20\u90fd\u8bbe\u4e3a 0<\/strong> \u3002\u8bf7\u4f7f\u7528 \u539f\u5730<\/a><\/strong> \u7b97\u6cd5\u3002<\/strong><\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n\u968f\u624b\u5199\u7684\uff0c\u65f6\u95f4\u590d\u6742\u5ea6O(MN)\uff0c\u4e00\u770b100%\u90a3\u884c\u4e86\u4e0d\u4f18\u5316\u4e86\u3002<\/p>\n\n\n\n
void setZeroes(vector<vector<int>>& matrix) {\n \/\/\u8003\u8651\u5230\u8fd9\u4e2aunordered_set\u662fO(1)\u67e5\u8be2\uff0c\u4e00\u5b9a\u7a0b\u5ea6\u4e0a\u4e5f\u8282\u7701\u7a7a\u95f4\n unordered_set<int> rows;\n unordered_set<int> cols;\n\n \/\/ \u884c\u6570\u5217\u6570\u505a\u597d\n int row_size = matrix.size();\n int col_size = matrix[0].size();\n\n \/\/ \u628a\u4e3a0\u7684\u884c\u6570\u5217\u6570\u52a0\u8fdb\u53bb\n for(int i = 0 ; i < row_size ; i++){\n for(int j = 0 ; j < col_size ; j++){\n if(matrix[i][j] == 0){\n rows.insert(i);\n cols.insert(j);\n }\n }\n }\n \/\/ \u5982\u679c\u884c\u6570\u6216\u8005\u5217\u6570\u5728set\u91cc\uff0c\u90a3\u5c31\u8bbe\u7f6e\u4e3a0\n for(int i = 0 ; i < row_size ; i++){\n for(int j = 0 ; j < col_size ; j++){\n if(rows.count(i) || cols.count(j)){\n matrix[i][j] = 0 ;\n }\n }\n }\n }<\/code><\/pre>\n\n\n\n\u87ba\u65cb\u77e9\u9635<\/h3>\n\n\n\n
\u7ed9\u4f60\u4e00\u4e2a m<\/code> \u884c n<\/code> \u5217\u7684\u77e9\u9635 matrix<\/code> \uff0c\u8bf7\u6309\u7167 \u987a\u65f6\u9488\u87ba\u65cb\u987a\u5e8f<\/strong> \uff0c\u8fd4\u56de\u77e9\u9635\u4e2d\u7684\u6240\u6709\u5143\u7d20\u3002<\/p>\n\n\n\n\u65cb\u8f6c\u5012\u4e0d\u662f\u95ee\u9898\uff0c\u5f00\u59cb\u6211\u6ca1\u60f3\u5230\u600e\u4e48\u505c\u4e0b\u6765\u3002\u6700\u540e\u4e00\u60f3\u76f4\u63a5\u5faa\u73afmn\u5c31\u884c\uff0c\uff0c\u7b80\u5355\u8584\u7eb1<\/p>\n\n\n\n
vector<int> spiralOrder(vector<vector<int>>& matrix) {\n \n int row = matrix.size() , col = matrix[0].size();\n int i = 0 , j = 0; \n int direction = 0 , circle = 0; \/\/1,2,3,4\u8868\u793a\u56db\u4e2a\u65b9\u5411\uff0ccircle\u8868\u793a\u8f6c\u4e86\u591a\u5c11\u5708\n vector<int> ans;\n \/\/\u4e00\u822c\u60c5\u51b5\u4e0b\u53f3\u8f6c\uff0c\u4f46\u662f\u5982\u679c\u662f\u7ad6\u6761\uff0c\u90a3\u4e48\u65b9\u5411\u8981\u5411\u4e0b\n if(col == 1) direction = 1;\n \/\/ \u4e0b\u9762\u662f\u6709\u70b9\u5c4e\u7684\uff0c\u7406\u8bba\u4e0a\u53ef\u4ee5\u5408\u5e76\u4e00\u5757\uff0c\u4e0d\u8fc7\u61d2\u5f97\u60f3\u4e86233333\n for(int k = 0 ; k < row * col ; k++)\n {\n ans.push_back(matrix[i][j]);\n if(direction == 0){\n j ++;\n \/\/\u62b5\u8fbe\u8fb9\u754c\uff0c\u6389\u5934\n if(j + circle >= col - 1)\n direction++;\n } else if(direction == 1){\n i ++;\n if(i + circle >= row -1)\n direction++;\n } else if(direction == 2){\n j --;\n if(j <= circle)\n {\n direction++;\n }\n } else if(direction == 3){\n i--;\n if(i <= circle + 1)\n {\n direction = 0;\n circle++;\n }\n }\n }\n return ans;\n }<\/code><\/pre>\n\n\n\n\u65cb\u8f6c\u56fe\u50cf<\/h3>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a n <\/em>\u00d7 n<\/em> \u7684\u4e8c\u7ef4\u77e9\u9635 matrix<\/code> \u8868\u793a\u4e00\u4e2a\u56fe\u50cf\u3002\u8bf7\u4f60\u5c06\u56fe\u50cf\u987a\u65f6\u9488\u65cb\u8f6c 90 \u5ea6\u3002
\u4f60\u5fc5\u987b\u5728 \u539f\u5730<\/a><\/strong> \u65cb\u8f6c\u56fe\u50cf\uff0c\u8fd9\u610f\u5473\u7740\u4f60\u9700\u8981\u76f4\u63a5\u4fee\u6539\u8f93\u5165\u7684\u4e8c\u7ef4\u77e9\u9635\u3002\u8bf7\u4e0d\u8981 <\/strong>\u4f7f\u7528\u53e6\u4e00\u4e2a\u77e9\u9635\u6765\u65cb\u8f6c\u56fe\u50cf\u3002<\/p>\n\n\n\n\u6570\u5b66\u9898\uff0c\u6ca1\u610f\u601d\u3002\u5148\u884c\u53cd\u8f6c\uff0c\u518d\u5bf9\u89d2\u7ebf<\/strong>\u3002\u5c31100%AC\u4e86<\/p>\n\n\n\nvoid rotate(vector<vector<int>>& matrix) {\n \/\/\u5148\u884c\u53cd\u8f6c\uff0c\u518d\u5bf9\u89d2\u7ebf\n int n = matrix.size();\n for(int i = 0 ; i < n \/2 ; i++){\n swap(matrix[i] , matrix[n - 1 - i]);\n }\n for(int i = 0 ; i < n ; i++){\n for(int j = i + 1 ; j < n ; j++){\n swap(matrix[i][j] , matrix[j][i]);\n }\n }\n }<\/code><\/pre>\n\n\n\n\u641c\u7d22\u4e8c\u7ef4\u77e9\u9635 II<\/h3>\n\n\n\n
\u7f16\u5199\u4e00\u4e2a\u9ad8\u6548\u7684\u7b97\u6cd5\u6765\u641c\u7d22 m x n \u77e9\u9635 matrix \u4e2d\u7684\u4e00\u4e2a\u76ee\u6807\u503c target \u3002\u8be5\u77e9\u9635\u5177\u6709\u4ee5\u4e0b\u7279\u6027\uff1a<\/p>\n\n\n\n
\u6bcf\u884c\u7684\u5143\u7d20\u4ece\u5de6\u5230\u53f3\u5347\u5e8f\u6392\u5217\u3002\u6bcf\u5217\u7684\u5143\u7d20\u4ece\u4e0a\u5230\u4e0b\u5347\u5e8f\u6392\u5217\u3002<\/p>\n\n\n\n
\u8111\u7b4b\u6025\u8f6c\u5f2f\uff0c\u770b\u8fc7\u5c31\u4f1a\u3002\u3002<\/p>\n\n\n\n
bool searchMatrix(vector<vector<int>>& matrix, int target) {\n \/\/ \u53f3\u4e0a\u89d2\u5f00\u59cb\u662f\u4e8c\u53c9\u641c\u7d22\u6811...\n int m = matrix.size() , n = matrix[0].size();\n int i = 0 , j = n - 1;\n while(i >= 0 && i < m && j >= 0 && j <n){\n if(target > matrix[i][j]){\n i++;\n }else if(target < matrix[i][j]){\n j--;\n }else {\n return true;\n }\n }\n return false;\n }<\/code><\/pre>\n\n\n\n\u76f8\u4ea4\u94fe\u8868<\/a><\/h3>\n\n\n\n<\/div><\/figure>\n\n\n\n\u4e5f\u662f\u5f88\u7ecf\u5178\u4e86\uff0c\u548c\u516c\u5171\u5c3e\u4e32\u601d\u8def\u4e00\u81f4\u3002<\/p>\n\n\n\n
\/**\n * Definition for singly-linked list.\n * struct ListNode {\n * int val;\n * ListNode *next;\n * ListNode(int x) : val(x), next(NULL) {}\n * };\n *\/\nclass Solution {\npublic:\n ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {\n ListNode *A = headA;\n ListNode *B = headB;\n\n int back = 0;\n while(back < 3 ){\n if(headA == headB) return headA;\n if(headA->next) headA = headA->next;\n else {\n headA = B;\n back++;\n }\n if(headB->next)headB = headB->next;\n else {\n headB = A;\n back++;\n }\n }\n return NULL;\n }\n};<\/code><\/pre>\n\n\n\n\u53cd\u8f6c\u94fe\u8868<\/a><\/h3>\n\n\n\n\u5f53\u521d\u53ef\u6ca1\u90a3\u4e48\u4f1a\uff0c\u90fd\u8981\u6c89\u601d\u5f88\u4e45\uff0c\u73b0\u5728\u5c45\u7136\u4e00\u4e0b\u5c31\u5199\u51fa\u6765\u4e86<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n\/**\n * Definition for singly-linked list.\n * struct ListNode {\n * int val;\n * ListNode *next;\n * ListNode() : val(0), next(nullptr) {}\n * ListNode(int x) : val(x), next(nullptr) {}\n * ListNode(int x, ListNode *next) : val(x), next(next) {}\n * };\n *\/\nclass Solution {\npublic:\n ListNode* reverseList(ListNode* head) {\n ListNode *cur , *temp , * pre = nullptr;\n cur = head;\n while(cur != nullptr){\n temp = cur->next; \/\/ temp\u7684\u76ee\u7684\u662f\u56e0\u4e3acur\u6389\u5934\u627e\u4e0d\u5230\u4e0b\u4e00\u4e2a\uff0c\u56e0\u6b64\u63d0\u524d\u9501\u5b9a\n cur->next = pre; \/\/ pre\u76ee\u7684\u662f\u5355\u5411\u94fe\u8868\u627e\u4e0d\u5230\u524d\u4e00\u4e2a\n pre = cur;\n cur = temp;\n }\n return pre;\n }\n};<\/code><\/pre>\n\n\n\n\u56de\u6587\u94fe\u8868<\/a><\/h3>\n\n\n\n\u7ed9\u4f60\u4e00\u4e2a\u5355\u94fe\u8868\u7684\u5934\u8282\u70b9 head<\/code> \uff0c\u8bf7\u4f60\u5224\u65ad\u8be5\u94fe\u8868\u662f\u5426\u4e3a\u56de\u6587\u94fe\u8868\u3002\u5982\u679c\u662f\uff0c\u8fd4\u56de true<\/code> \uff1b\u5426\u5219\uff0c\u8fd4\u56de false<\/code> \u3002<\/p>\n\n\n\n\u5feb\u6162\u6307\u9488\u627e\u4e2d\u95f4\uff0c\u7ffb\u8f6c\u540e\u7eed\u5c31\u90fd\u662f\u987a\u5e8f\u4e86\u3002\u6bd4\u8f83\u5373\u53ef<\/p>\n\n\n\n
class Solution {\npublic:\n ListNode* reverse(ListNode* head){\n ListNode *cur , *temp , *pre = nullptr;\n cur = head;\n while(cur){\n temp = cur->next;\n cur->next = pre;\n pre = cur;\n cur = temp;\n }\n return pre;\n }\n bool isPalindrome(ListNode* head) {\n \/\/ O(n)\u7a7a\u95f4\u90a3\u5c31\u592a\u7b80\u5355\u4e86\uff0c\u4f46\u662fO(1)\n \/\/ \u5feb\u6162\u6307\u9488\u627e\u4e2d\u95f4\uff0c\u53cd\u8f6c\u540e\u7eed\u6bd4\u8f83\n ListNode *fast = head, * slow = head;\n \n \/\/\u5148\u627e\u5230\u7ffb\u8f6c\u70b9\n \/\/ \u4fdd\u8bc1slow\u5728\u9700\u8981\u7ffb\u8f6c\u7684\u524d\u4e00\u4e2a\uff08\u65e0\u8bba\u5947\u5076\uff09\n while(1){\n if(fast->next) {\n fast = fast->next;\n } \n if(fast->next){\n fast = fast->next;\n slow = slow->next;\n } else{\n break;\n }\n }\n\n \/\/\u73b0\u5728\u7ffb\u8f6c,\u6bd4\u8f83\u6bcf\u4e00\u4e2a\uff0c\u76f4\u5230\u6700\u540e\n ListNode* end = reverse(slow->next) ,* start = head;\n while(end){ \/\/\u7528\u540e\u9762\u8fd9\u4e2a\u662f\u56e0\u4e3a\u4ed6\u77ed\n if(end->val != start->val) return false;\n end = end->next;\n start = start->next;\n }\n return true;\n }\n};<\/code><\/pre>\n\n\n\n\u73af\u5f62\u94fe\u8868<\/a><\/h3>\n\n\n\n\u7ed9\u4f60\u4e00\u4e2a\u94fe\u8868\u7684\u5934\u8282\u70b9 head<\/code> \uff0c\u5224\u65ad\u94fe\u8868\u4e2d\u662f\u5426\u6709\u73af<\/p>\n\n\n\n\u4e00\u773c\u4e01\u771f\uff0c\u5feb\u6162\u6307\u9488\uff0c\u8fc7\u3002\u6211\u5f88\u597d\u5947\u4e3a\u4ec0\u4e48\u6211\u53ea\u8d85\u8fc720%\u4f46\u590d\u6742\u5ea6\u6700\u4f18\uff0c\u53d1\u73b0\u7b2c\u4e00\u540d\u539f\u6765\u662f\u68c0\u6d4b\u5faa\u73af\u8d70\u4e8610000\u8fd8\u5728\u8d70\u5c31\u662f\u6709\u73af\u3002\u3002\u3002\u3002\u3002\u3002\u9006\u5929<\/p>\n\n\n\n
bool hasCycle(ListNode *head) {\n ListNode *fast = head , *slow = head;\n if(head == NULL || head->next ==NULL) return false;\n fast = head->next->next;\n slow = head->next;\n while(fast){\n if(fast == slow){\n return true;\n }\n fast = fast->next;\n if(fast == NULL) return false;\n fast = fast->next;\n slow = slow->next;\n }\n return false;\n }<\/code><\/pre>\n\n\n\n\u73af\u5f62\u94fe\u8868 II<\/a><\/h3>\n\n\n\n\u6570\u5b66\u63a8\u5230\u7c7b\u578b\uff0c\u60f3\u51fa\u6765\u5c31\u4f1a<\/p>\n\n\n\n
ListNode *detectCycle(ListNode *head) {\n \/\/\u5feb\u6162\u6307\u9488\u8d70\uff0c\u76f8\u9047\u4e4b\u540e\u5728\u4ece\u5934\u6765\u4e00\u4e2a\u6307\u9488\uff0c\u76f8\u9047\u70b9\u5c31\u662f\u73af\u7684\u4f4d\u7f6e\u3002\n ListNode *fast = head , *slow = head;\n if(head == NULL || head->next ==NULL) return NULL;\n fast = head->next->next;\n slow = head->next;\n while(fast){\n if(fast == slow){\n ListNode *start = head;\n while(start != slow){\n start = start->next;\n slow = slow->next;\n }\n return start;\n }\n fast = fast->next;\n if(fast == NULL) return NULL;\n fast = fast->next;\n slow = slow->next;\n }\n return NULL;\n }<\/code><\/pre>\n\n\n\n\u5408\u5e76\u4e24\u4e2a\u6709\u5e8f\u94fe\u8868<\/a><\/h3>\n\n\n\n\u7ecf\u5178\u9898\uff0c\u4e0d\u8d58\u8ff0<\/p>\n\n\n\n
ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) {\n ListNode *mergeList = new ListNode();\n ListNode *head = mergeList;\n \/\/ \u8c01\u5c0f\u8c01\u4e0b\u4e00\u4e2a\n while(list1 && list2){\n if(list1->val < list2->val){\n mergeList->next = list1 ;\n list1 = list1->next;\n } else {\n mergeList->next = list2;\n list2 = list2->next;\n }\n mergeList = mergeList->next;\n }\n if(list1) mergeList->next = list1;\n else mergeList->next =list2;\n return head->next;\n }<\/code><\/pre>\n\n\n\n\u4e24\u6570\u76f8\u52a0<\/a><\/h3>\n\n\n\n\u9006\u5e8f\u6570\u76f8\u52a0\uff0c\u5982\u56fe\u662f342 + 465 = 807.<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n\u6709\u70b9\u5570\u55e6\uff0c\u4f46\u662f100%AC\uff0c\u7ec6\u8282\u4e0d\u4f18\u5316\u4e86<\/p>\n\n\n\n
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {\n ListNode* current_node = new ListNode();\n ListNode* head = current_node;\n int current = 0 , next = 0;\n \/\/\u76f8\u52a0\uff0c\u5b58\u5230\u4e00\u76f4\u8282\u70b9\u3002\u8bb0\u5f55\u8fdb\u4f4d\n while(l1 && l2){\n int sum = l1->val + l2->val + next;\n current = sum % 10;\n next = sum \/ 10;\n l1->val = current;\n current_node->next = l1;\n current_node = current_node->next;\n\n l1 = l1->next;\n l2 = l2->next;\n }\n \/\/ \u5982\u679c\u4e00\u8fb9\u957f\u4e00\u8fb9\u77ed\uff0c\u90a3\u4e48\u8fd8\u8981\u63a5\u7740\u7b97\n while(l1){\n int sum = l1->val + next;\n current = sum % 10;\n next = sum \/ 10;\n l1->val = current;\n current_node->next = l1;\n current_node = current_node->next;\n\n l1 = l1->next; \n if(next == 0) break;\n }\n while(l2){\n int sum = l2->val + next;\n current = sum % 10;\n next = sum \/ 10;\n l2->val = current;\n current_node->next = l2;\n current_node = current_node->next;\n\n l2 = l2->next; \n if(next == 0) break;\n }\n \/\/ \u6700\u540e\u8fd8\u8fdb\u4f4d\uff0c\u591a\u52a0\u4e00\u4e2a\u8282\u70b9\n if(next == 1){\n ListNode* up = new ListNode(1);\n current_node->next = up;\n \/\/ new node\n }\n return head->next;<\/code><\/pre>\n\n\n\n\u5220\u9664\u94fe\u8868\u7684\u5012\u6570\u7b2c N \u4e2a\u7ed3\u70b9<\/a><\/h3>\n\n\n\n\u5feb\u6162\u6307\u9488\u79d2\u4e86\u3002\u4e00\u4e2a\u6307\u9488\u5febN\u4e2a\uff0c\u90a3\u4e2a\u5230\u7ed3\u5c3e\u8fd9\u4e2a\u5c31\u5220<\/p>\n\n\n\n
\u5220\u9664\u94fe\u8868\u7684\u5012\u6570\u7b2c N \u4e2a\u7ed3\u70b9<\/a><\/h3>\n\n\n\n<\/div><\/figure>\n\n\n\n ListNode* removeNthFromEnd(ListNode* head, int n) {\n ListNode* fast = head , *slow = head ;\n \/\/\u4fdd\u6301\u9886\u5148N\u4e2a\uff0c\u5982\u679c\u6b64\u65f6\u4e3a\u7a7a\uff0c\u5219\u8bf4\u660e\u94fe\u8868\u957f\u5ea6\u548c\u8981\u5220\u7684\u4e00\u6837\u591a\uff0c\u90a3\u4e48\u5c31\u53bb\u6389\u7b2c\u4e00\u4e2a\u5c31\u597d\n while(n --) fast = fast->next;\n if(!fast) return head->next;\n \/\/\u540e\u9762\u5c31\u662f\u4fdd\u6301\u9886\u5148n+1\u4e2a\uff0c\u8fd9\u6837\u65b9\u4fbf\u5220\n fast = fast->next;\n while(fast ) {\n fast = fast->next;\n slow = slow->next;\n }\n slow->next = slow->next->next;\n return head;\n }<\/code><\/pre>\n\n\n\n\u4e24\u4e24\u4ea4\u6362\u94fe\u8868\u4e2d\u7684\u8282\u70b9<\/a><\/h3>\n\n\n\n ListNode* swapPairs(ListNode* head) {\n ListNode* start = new ListNode();\n \/\/ \u8f85\u52a9\u8d77\u70b9\n start->next = head;\n ListNode* left = start, * mid = head, *right = nullptr;\n \n \/\/\u5f53\u524d\u8981\u4ea4\u6362\u4fe9\u8282\u70b9\u4e3a\u7a7a\n while(mid && mid->next){\n \/\/\u4ea4\u6362\n right = mid->next;\n mid->next = right->next;\n left->next=right;\n right->next = mid;\n\n \/\/\u4ea4\u6362\u5b8c\u6210\u540e\u8c03\u6574\n left = mid;\n mid = mid->next;\n }\n\n return start->next;\n }<\/code><\/pre>\n\n\n\nK \u4e2a\u4e00\u7ec4\u7ffb\u8f6c\u94fe\u8868<\/a><\/h3>\n\n\n\n\u9898\u662f\u4e0d\u96be\uff0c\u4f46\u662f\u8981\u6ce8\u610f\u8fb9\u754c\u60c5\u51b5\u3002\u8fd9\u91cc\u6211\u6574\u4e86\u5f88\u4e45\uff0c\u8981\u6ce8\u610f\u51e0\u4e2a\u70b9\uff0c\u6bd4\u5982\u5f00\u59cb\u7684\u5934\u8282\u70b9\u4e0d\u8981\u5f80\u540e\u8dd1\u4e86<\/p>\n\n\n\n
\/**\n * Definition for singly-linked list.\n * struct ListNode {\n * int val;\n * ListNode *next;\n * ListNode() : val(0), next(nullptr) {}\n * ListNode(int x) : val(x), next(nullptr) {}\n * ListNode(int x, ListNode *next) : val(x), next(next) {}\n * };\n *\/\nclass Solution {\npublic:\n ListNode* reverse(ListNode* head){\n ListNode *pre = nullptr , * cur = head , *temp;\n while(cur){\n temp = cur->next;\n cur->next = pre;\n pre = cur;\n cur = temp;\n }\n return pre;\n }\n\n ListNode* reverseKGroup(ListNode* head, int k) {\n \/\/\u4e00\u4e2a\u7b80\u5355\u7684\u601d\u8def\n \/\/ \u6211\u8981\u7ffb\u8f6c\u4e00\u6bb5\uff0c\u6211\u5c31\u628a\u8fd9\u4e00\u6bb5\u524d\u540e\u90fd\u65ad\u4e86\uff0c\u5e76\u8bb0\u5f55\u5934\uff08\u5c3e\u4f1a\u53d8\u6210\u5934\u4e0d\u7528\u7ba1\uff09\uff0c\u548c\u8fd9\u4e00\u6bb5\u524d\u548c\u540e\n \/\/ \u5224\u65ad\u662f\u5426\u8981\u7ffb\u8f6c\u5c31\u6392\u4e00\u4e2a\u54e8\u5175\u51fa\u53bb\uff0c\u80fd\u8dd1\u5230\u6307\u5b9a\u4f4d\u7f6e\u4e0d\u4e3a\u7a7a\u5c31\u80fd\n ListNode* hair = new ListNode();\n hair->next = head;\n\n ListNode* pre = hair , *A = head;\n ListNode* B = pre, * end = nullptr;\n\n\n while(1){\n for(int i = 0 ; i < k; i++) {\n B = B->next;\n if(!B) return hair->next;\n }\n end = B->next;\n\n B->next = nullptr;\n pre->next = reverse(A);\n A->next = end;\n\n pre = A ;\n A = end ;\n B = pre ;\n }\n return hair->next;\n }\n};<\/code><\/pre>\n\n\n\n\u968f\u673a\u94fe\u8868\u7684\u590d\u5236<\/a><\/h2>\n\n\n\n\u610f\u601d\u5c31\u662f\uff0c\u4f60\u62f7\u8d1d\u4e00\u4e2anode\u65f6\u5019\uff0c\u91cc\u9762\u7684\u6307\u9488\u5185\u5bb9\uff0c\u4f60\u4e5f\u8981\u62f7\u8d1d\u5230\u65b0\u7684\u91cc\u9762\u3002\u7406\u89e3\u4e4b\u540e\u968f\u4fbf\u6740<\/p>\n\n\n\n
Node* copyRandomList(Node* head) {\n unordered_map< Node* , Node*> mp;\n\n Node *start = head;\n Node *newList = new Node(0) ;\n Node *cur = newList;\n \/\/\u5148\u8fc7\u4e00\u904d\uff0c\u54c8\u5e0c\u8868\u5bf9\u5e94\u4e0a\n while(start){\n Node *node = new Node(start->val);\n cur->next = node;\n mp[start] = node;\n start = start->next;\n cur = cur->next;\n } \n \/\/\u518d\u8fc7\u4e00\u904d\uff0c\u627e\u5230random\n Node *newHead = newList->next;\n Node *oldList = head;\n while(newHead){\n newHead->random = mp[oldList->random];\n oldList = oldList->next;\n newHead = newHead->next;\n }\n return newList->next;\n }<\/code><\/pre>\n\n\n\n\u6392\u5e8f\u94fe\u8868<\/a><\/h3>\n\n\n\n\u7ed9\u4f60\u94fe\u8868\u7684\u5934\u7ed3\u70b9 head<\/code> \uff0c\u8bf7\u5c06\u5176\u6309 \u5347\u5e8f<\/strong> \u6392\u5217\u5e76\u8fd4\u56de \u6392\u5e8f\u540e\u7684\u94fe\u8868<\/strong> \u3002<\/p>\n\n\n\nmergesort\uff0c\u5feb\u6162\u6307\u9488\u627e\u4e2d\u70b9\uff0c\u7136\u540e\u5f52\u5e76<\/p>\n\n\n\n
\u5408\u5e76 K \u4e2a\u5347\u5e8f\u94fe\u8868<\/a><\/h3>\n\n\n\n\u4fe9\u4fe9\u5408\u5e76\uff0c\u6211\u8fd9\u91cc\u7528\u4e86\u961f\u5217\u5f88\u65b9\u4fbf\u3002\u6ce8\u610f\u662ffront\uff0cpush\uff0cpop\u3002\u6ca1\u8bed\u6cd5\u63d0\u793a\u597d\u7d2f223333333<\/p>\n\n\n\n
ListNode* mergeList(ListNode *a , ListNode *b){\n ListNode *head = new ListNode();\n ListNode *cur = head;\n while(a && b){\n if(a->val < b->val){\n cur->next = a;\n a = a->next;\n } else {\n cur->next = b;\n b = b->next;\n }\n cur = cur->next;\n }\n if(a) cur->next = a;\n else if(b) cur->next = b;\n return head->next;\n }\npublic:\n ListNode* mergeKLists(vector<ListNode*>& lists) {\n if(lists.size() == 0) return nullptr;\n queue<ListNode*> q;\n for(int i = 0 ; i < lists.size() ; i++){\n q.push(lists[i]);\n }\n while(q.size() >= 2){\n ListNode *node1 = q.front();\n q.pop();\n ListNode *node2 = q.front();\n q.pop();\n q.push(mergeList(node1 , node2));\n }\n return q.front();\n }<\/code><\/pre>\n\n\n\n\u6392\u5e8f\u94fe\u8868<\/a><\/h3>\n\n\n\n\u65f6\u95f4\u590d\u6742\u5ea6\u7b26\u5408\u8981\u6c42\uff0c\u7a7a\u95f4\u4e0d\u7b26\u5408\u3002\u8fd8\u6709\u6700\u540e\u7684\u5408\u5e76\u94fe\u8868\u5c45\u7136\u5199\u9519\u4e86\u786c\u662f\u53d1\u73b0\u4e0d\u4e86\u3002\u3002\u3002\u4e00\u957f\u5c31\u4f1a\u9519\u771f\u70e6\u4eba\u3002<\/p>\n\n\n\n
class Solution {\npublic:\n ListNode* sortList(ListNode* head) {\n return devide(head);\n }\n ListNode *devide(ListNode* head){\n if(head == nullptr) return nullptr;\n if(head->next == nullptr) return head;\n cout << head->val << head->next->val;\n ListNode *fast = head,*slow = head;\n while(fast){\n fast = fast->next;\n if(fast) {\n fast = fast->next;\n if(fast) slow = slow->next;\n }\n } \n ListNode *start = slow->next;\n slow->next = nullptr;\n\n ListNode *left = devide(head);\n ListNode *right = devide(start);\n return merge(left , right);\n }\n\n ListNode* merge(ListNode *L1 , ListNode *L2){\n ListNode *head = new ListNode();\n ListNode *temp = head;\n while(L1 && L2){\n if(L1->val < L2->val){\n temp->next = L1;\n L1 = L1->next;\n }else {\n temp->next = L2;\n L2 = L2->next;\n }\n temp = temp->next;\n }\n if(L1) temp->next = L1;\n else temp->next = L2;\n return head->next;\n }\n};<\/code><\/pre>\n\n\n\nLRU \u7f13\u5b58<\/a><\/h3>\n\n\n\n
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