Reference: http://blog.csdn.net/lbyxiafei/article/details/9375735  题目: Implement int sqrt(int x). Compute and return the square root of x. 题解: 这道题很巧妙的运用了二分查找法的特性,有序,查找pos(在这道题中pos=value),找到返回pos,找不到返回邻近值. 因为是求数x(x>=0) 的平方根, 因此,结果一定是小于等于x且大于等于0,所以用二分查…

题目: Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. 题解: 这道题跟NQueens的解法完全一样(具体解法参照N QueensN Queens leetcode java),只不过要求的返回值不同了..所以要记录的result稍微改一下就好了... 因为涉及到递归,result传进去引用类型(…

题目: The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) P A H N A P L S I I G Y I R And then read line by line: "PAHNAP…

Candy There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more ca…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…

问题描述: There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you toggle every third bulb (turning on if it's off or turning off if it's on). For the nth round, you only tog…

问题描述: Given 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. Could you implement it without using extra memory? 提示:bit manipulation(位操作) 参考:http…

题目: Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible representation of s1 = "great": great / \ gr eat / \ / \ g r e at / \ a t To scramble the string, we ma…

题目: Implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). The function prototype shoul…

题目: Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the". click to show clarification. Clarification: What constitutes a word? A sequence of non-space characters con…