强威

摘要： You are given a list of non-negative integers, a1, a2, ..., an, and a target, S. Now you have 2 symbols + and -. For each integer, you should choose o 阅读全文

摘要： Given a non-empty array of integers, return the k most frequent elements. Example 1: Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Example 2: Input 阅读全文

摘要： Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: 阅读全文

摘要： 1.形如 T(n) = a * T(n/b) + f(n) 的时间复杂度计算方法 有一种方法叫做主方法（Master method）是用来专门计算这种形式的时间复杂度的，方法具体如下： 下边举例进行说明： 例1： T(n) = 25*T(n/5) + n^2 因为：a=25,b=5,d=2,f(n) 阅读全文

摘要： A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any p 阅读全文

摘要： Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. Example: Given a matrix of m x n elements (m r 阅读全文

摘要： Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that the intervals were initia 阅读全文

摘要： Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example: Foll 阅读全文

摘要： class Solution { public: int trap(vector<int>& height) { int l = 0, r = height.size()-1, level = 0, water = 0; while (l < r) { int lower = height[height[l] < height[r] ? l++ : r--]; level = max(level, 阅读全文

摘要： 1.顺时针： You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place 阅读全文