摘要： Given an array of strings, group anagrams together. Example: Note: All inputs will be in lowercase. The order of your output does not matter. 基本的遍历练手题 阅读全文

摘要： 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, which 阅读全文

摘要： Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. 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： 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 an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example: Inpu 阅读全文

摘要： Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string "". Exampl 阅读全文

摘要： Given n, how many structurally unique BST's (binary search trees) that store values 1 ... n? Example: Input: 3 Output: 5 Explanation: Given n = 3, the 阅读全文

摘要： A message containing letters from A-Z is being encoded to numbers using the following mapping: Given a non-empty string containing only digits, determ 阅读全文

摘要： You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you cl 阅读全文