qq_17480053的博客

Top K Frequent ElementsGiven a non-empty array of integers, return the k most frequent elements.For example,Given [1,1,1,2,2,3] and k = 2, return [1,2].Note: You may

Given a 2D board containing 'X' and 'O' (the letter O), capture all regions surrounded by 'X'.A region is captured by flipping all 'O's into 'X's in that surrounded region.For example,X X X

search for a rangeGiven a sorted array of integers, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the order of O(log n).If the

Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue.Here, we will use the integers 0,

刷leetcode的时候，发现了很多使用到x&(x-1)的题目。顺便在网上查了查，做了总结：求下面函数的返回值(微软) -- 统计1的个数-------------------------------------int func(int x){    int countx = 0;    while(x)    {        countx++;

Group AnagramsGiven an array of strings, group anagrams together.For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], Return:[ ["ate", "eat","tea"], ["nat","

Construct Binary Tree from Preorder and Inorder TraversalGiven preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not

Kth Smallest Element in a BSTGiven a binary search tree, write a function kthSmallest to find thekth smallest element in it.Note: You may assume k is always valid, 1 ≤ k ≤

Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1].

Given a collection of distinct numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1],[3,1,2], and [3,2,1].看完一遍题

Single Number IIGiven an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity

Power of TwoTotal Accepted: 3596 Total Submissions: 11779Given an integer, write a function to determine if it is a power of two.Credits:Special thanks to @jianchao.li.fighter for addi

Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and return them as an array.Example:For num = 5 y

Lowest Common Ancestor of a Binary TreeGiven a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.According to the definition of LCA on Wikipedia: “The lowest

There are N gas stations along a circular route, where the amount of gas at stationi is gas[i].You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from stationi to it

Number of Digit OneGiven an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.For example:Given n = 13,Return 6, because digit 1 o