摘要： Suppose a sorted array is rotated at some pivot unknown to you beforehand.     (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).     Find the minimum 阅读全文

摘要： The gray code is a binary numeral system where two successive values differ in only one bit. Given a non-negative integer n representing the total num 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 a 阅读全文

摘要： Write an algorithm to determine if a number is "happy".     A happy number is a number defined by the following process: Starting with any positive in 阅读全文