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LeetCode 327. Count of Range Sum
离散化 + 树状数组。原创 2022-10-09 06:31:11 · 181 阅读 · 0 评论 -
LeetCode 315. Count of Smaller Numbers After Self
【代码】LeetCode 315. Count of Smaller Numbers After Self。原创 2022-10-03 01:19:38 · 492 阅读 · 0 评论 -
LeetCode 324. Wiggle Sort II
LeetCode 题解原创 2022-09-26 06:50:33 · 155 阅读 · 0 评论 -
LeetCode 809. Expressive Words | two pointer | 题意分析
Example:Input: S = "heeellooo"words = ["hello", "hi", "helo"]Output: 1Explanation: We can extend "e" and "o" in the word "hello" to get "heeellooo".We can't extend "helo" to get "heeellooo" because the group "ll" is not size 3 or more.题意分析个人觉得反.原创 2020-06-05 07:12:27 · 236 阅读 · 0 评论 -
LeetCode - Top K Frequent Elements
解法一：class Solution {public: vector<int> topKFrequent(vector<int>& nums, int k) { unordered_map<int, int> m; priority_queue<pair<int, int>> q;...原创 2018-09-12 05:49:03 · 393 阅读 · 0 评论 -
LeetCode - Sort Characters By Frequency
解法一：class Solution {public: string frequencySort(string s) { unordered_map<char, int> temp; vector<vector<char>> bucket(s.size()+1); string res=""; ...原创 2018-09-12 12:32:18 · 233 阅读 · 0 评论 -
LeetCode - 57. Insert Interval
57. Insert IntervalPlease keep it simple!class Solution(object): def insert(self, intervals, newInterval): """ :type intervals: List[List[int]] :type newInterval: List...原创 2018-09-18 06:59:37 · 122 阅读 · 0 评论 -
LeetCode - 56. Merge Intervals
56. Merge Intervalsclass Solution(object): def merge(self, intervals): """ :type intervals: List[List[int]] :rtype: List[List[int]] """ if len(intervals)...原创 2018-09-18 07:05:37 · 213 阅读 · 1 评论 -
LeetCode - Intersections of Two Arrays
两个array中有什么重复元素。insert input arrays into set 跟 sorting 基本可以替换，但是set需要extra spaceset_intersection 又可以和 two pointers 找相同元素可以替换set search 也可以和 binary search 替换选你喜欢的组合吧～解法一set insert / search ...原创 2018-09-18 13:00:02 · 108 阅读 · 0 评论 -
LeetCode - Sort List C++
解法一：快速排序class Solution {public: ListNode* sortList(ListNode* head) { if(!head || !head->next) return head; ListNode* cur = head->next; ListNode* small = new Lis...原创 2018-09-18 16:51:35 · 124 阅读 · 0 评论 -
LeetCode - Largest Number
class Solution {public: string largestNumber(vector<int>& nums) { if(nums.empty()) return "0"; vector<string> str; string res=""; for(int a: nums)...原创 2018-09-24 12:54:38 · 122 阅读 · 0 评论 -
LeetCode - 621. Task Scheduler | Array | Python | C++
class Solution {public: int leastInterval(vector<char>& tasks, int n) { if(tasks.empty()) return 0; vector<int> count(26,0); for(char task:tasks){ ...原创 2018-09-25 15:33:55 · 245 阅读 · 0 评论 -
LeetCode - Assign Cookies
正解class Solution {public: int findContentChildren(vector<int>& g, vector<int>& s) { if(g.empty() || s.empty()) return 0; sort(g.begin(), g.end()); s...原创 2018-09-25 17:01:06 · 119 阅读 · 0 评论 -
LeetCode - Non-overlapping Intervals
结束的早不容易跟之后的overlapclass Solution {public: int eraseOverlapIntervals(vector<Interval>& intervals) { if(intervals.empty()) return 0; sort(intervals.begin(), intervals.e...原创 2018-09-25 17:58:17 · 119 阅读 · 0 评论 -
LeetCode - Minimum Number of Arrows to Burst Balloons
class Solution {public: int findMinArrowShots(vector<pair<int, int>>& points) { if(points.empty()) return 0; sort(points.begin(), points.end()); int pre_e...原创 2018-09-25 18:40:48 · 110 阅读 · 0 评论 -
LeetCode - Queue Reconstruction by Height
先身高从大到小，前面的人数从小到大排序按照排序，在相同“前面人数”的元素前insert，后insert的身高小于之前insert的身高class Solution {public: vector<pair<int, int>> reconstructQueue(vector<pair<int, int>>& people)...原创 2018-09-25 19:40:37 · 160 阅读 · 0 评论 -
LeetCode - Partition Labels
解法一class Solution {public: vector<int> partitionLabels(string S) { vector<pair<int,int>> t(26,make_pair(-1,-1)); for(int i=0;i<S.size();i++){ t...原创 2018-09-26 08:09:36 · 146 阅读 · 0 评论 -
LeetCode - Can Place Flowers
class Solution {public: bool canPlaceFlowers(vector<int>& flowerbed, int n) { if(n==0) return true; if(flowerbed.size()==1 && n==1) return flowerbed...原创 2018-09-26 08:35:38 · 109 阅读 · 0 评论 -
LeetCode - Is Subsequence
class Solution {public: bool isSubsequence(string s, string t) { if(s.empty()) return true; if(t.empty()) return false; int p1 = 0; int p2 = 0; while(p2&l...原创 2018-09-26 08:46:19 · 96 阅读 · 0 评论 -
LeetCode - Non-decreasing Array
class Solution {public: bool checkPossibility(vector<int>& nums) { if(nums.size()<=1) return true; int res=0; for(int i=1;i<nums.size();i++){ ...原创 2018-09-26 09:21:17 · 91 阅读 · 0 评论 -
LeetCode - Best Time to Buy and Sell Stock II
class Solution {public: int maxProfit(vector<int>& prices) { if(prices.size()<=1) return 0; int res = 0; for(int i=1;i<prices.size();i++){ if(...原创 2018-09-26 11:30:40 · 105 阅读 · 0 评论 -
LeetCode - Patching Array
class Solution {public: int minPatches(vector<int>& nums, int n) { long miss = 1; int res=0, i=0; while(miss<=n){ if(i<nums.size() && ...原创 2018-09-26 12:45:46 · 139 阅读 · 0 评论 -
LeetCode - Gas Station
class Solution {public: int canCompleteCircuit(vector<int>& gas, vector<int>& cost) { int n = gas.size(); if(n<1) return 0; vector<int> t(2*n...原创 2018-09-26 13:54:53 · 154 阅读 · 0 评论 -
LeetCode - Jump Game
解法一： DPdp[i]代表走到i position后最多可以继续可以走到的position。dp[i] = max(dp[i-1], i+nums[i]);如果dp[i-1]>=i, 继续遍历。反之，return false。class Solution {public: bool canJump(vector<int>& nums) { ...原创 2018-09-26 14:25:50 · 223 阅读 · 0 评论 -
LeetCode - Course Schedule
解法一：DFSneed to take this class what I need to take firstclass Solution {public: bool canFinish(int numCourses, vector<pair<int, int>>& prerequisites) { vector<int&...原创 2018-10-02 16:20:02 · 131 阅读 · 0 评论 -
LeetCode - Flatten Binary Tree to Linked List
解法一：recursion DFSclass Solution {public: void flatten(TreeNode* root) { if(!root) return; flatten(root->left); flatten(root->right); if(root->left){ ...原创 2018-10-02 17:53:39 · 130 阅读 · 0 评论 -
LeetCode - Binary Tree Right Side View
解法一： recursionclass Solution {public: vector<int> rightSideView(TreeNode* root) { if(!root) return {}; vector<int> left = rightSideView(root->left); vect...原创 2018-10-03 07:42:09 · 188 阅读 · 0 评论 -
LeetCode - Sudoku Solver
解法一：use three extra 2D vectorsclass Solution {public: bool helper(vector<vector<char>>& board, vector<vector<bool>>& row, vector<vector<bool>>&a原创 2018-10-11 16:43:45 · 123 阅读 · 0 评论 -
LeetCode - Subsets II
解法一：non-recursionclass Solution {public: vector<vector<int>> subsetsWithDup(vector<int>& nums) { vector<vector<int>> res; sort(nums.begin(), n...原创 2018-10-11 19:38:53 · 143 阅读 · 0 评论 -
LeetCode - Subsets
基本：每一个元素要还是不要，所以总共2^n个subsets解法一：BFS non-recursionuse an extra vectorclass Solution {public: vector<vector<int>> subsets(vector<int>& nums) { vector<vect...原创 2018-10-04 06:52:02 · 222 阅读 · 0 评论 -
LeetCode - Letter Combinations of a Phone Number
解法一：non-recursionclass Solution {public: vector<string> letterCombinations(string digits) { unordered_map<char, string> source = {{'2',"abc"}, {'3',"def"}, {'4',"ghi"}, ...原创 2018-10-04 08:54:16 · 172 阅读 · 0 评论 -
LeetCode - Path Sum
class Solution {public: bool hasPathSum(TreeNode* root, int sum) { if(!root) return false; if(!root->left && !root->right && root->val==sum) return true;...原创 2018-10-04 10:25:58 · 101 阅读 · 0 评论 -
LeetCode - Path Sum II
解法一：recursionclass Solution {public: vector<vector<int>> pathSum(TreeNode* root, int sum) { vector<vector<int>> res; vector<int> out; help...原创 2018-10-04 11:50:22 · 107 阅读 · 0 评论 -
LeetCode - 200. Number of Islands | DFS | BFS | Union Find
class Solution {public: int numIslands(vector<vector<char>>& grid) { if(grid.empty() || grid[0].empty()) return 0; int res = 0; for(int i=0;i<grid.size...原创 2018-09-27 13:42:00 · 152 阅读 · 0 评论 -
LeetCode - Permutations
解法一：DFS recursionclass Solution {public: vector<vector<int>> permute(vector<int>& nums) { vector<vector<int>> res; vector<int> out; ...原创 2018-10-05 12:50:28 · 299 阅读 · 0 评论 -
LeetCode - Permutations II
解法一：recursionclass Solution {public: vector<vector<int>> permuteUnique(vector<int>& nums) { if(nums.empty()) return {}; vector<vector<int>> re...原创 2018-10-05 13:57:24 · 128 阅读 · 0 评论 -
LeetCode - Combinations
解法一：DFS recursionclass Solution {public: vector<vector<int>> combine(int n, int k) { vector<vector<int>> res; vector<int> out; helper(n, k...原创 2018-10-05 15:38:18 · 135 阅读 · 0 评论 -
LeetCode - Combinations Sum
class Solution {public: vector<vector<int>> combinationSum(vector<int>& candidates, int target) { vector<vector<int>> res; vector<int> out...原创 2018-10-05 16:09:51 · 126 阅读 · 0 评论 -
LeetCode - Combination Sum III
class Solution {public: vector<vector<int>> combinationSum3(int k, int n) { vector<vector<int>> res; vector<int> out; helper(k, n, 1, out, r...原创 2018-10-12 17:32:15 · 195 阅读 · 0 评论 -
LeetCode - Validate IP Address
class Solution {public: string validIPAddress(string IP) { istringstream is(IP); string s = ""; int cnt = 0; if(IP.find(".")!=string::npos){ //IPv4 if...原创 2018-10-13 11:12:06 · 173 阅读 · 0 评论