sunshisonghit

摘要： Validate Binary Search Tree问题：Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left sub... 阅读全文

摘要： Word Ladder问题:Given two words (startandend), and a dictionary, find the length of shortest transformation sequence fromstarttoend, such that:Only one ... 阅读全文

摘要： 基于快速排序的TOPK算法转自：http://blog.csdn.net/fanzitao/article/details/7617223思想：类似于快速排序，首先选择一个划分元，如果这个划分元的序号index刚好等于k，那么这个划分元以及左边的数，刚好组成了top-k small data;如果i... 阅读全文

摘要： Number of 1 Bits问题：Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as theHamming weight).For exa... 阅读全文

摘要： Word Search问题：Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell,... 阅读全文

摘要： Rotate Array问题：Rotate an array ofnelements to the right byksteps.For example, withn= 7 andk= 3, the array[1,2,3,4,5,6,7]is rotated to[5,6,7,1,2,3,4].思... 阅读全文

摘要： Reverse Words in a String问题：Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".思路... 阅读全文