摘要：
Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique paths would there be?An obstacle and empty space i... 阅读全文
摘要：
A robot is located at the top-left corner of amxngrid (marked 'Start' in the diagram below).The robot can only move either down or right at any point ... 阅读全文
摘要：
Given an array of integers and an integerk, find out whether there are two distinct indicesiandjin the array such thatnums[i] = nums[j]and the differe... 阅读全文