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Invert a binary tree. 4 / \ 2 7 / \ / \1 3 6 9to 4 / \ 7 2 / \ / \9 6 3 1即反转二叉树，代码如下：/** * Definition for a bina... 阅读全文
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Given a column title as appear in an Excel sheet, return its corresponding column number.For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 ... 阅读全文
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The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ...1is read off as"one 1"or11.11is read off as"tw... 阅读全文
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1、方便获取图标的网站： http://www.easyicon.cn/ 2、百度网盘搜索引擎： http://www.pan1234.com/ 3、鸡啄米：C++编程入门系列之目录和总结： http://www.jizhuomi.com/software/129.html 4、牛客网：http:/ 阅读全文
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Find the total area covered by tworectilinearrectangles in a2Dplane.Each rectangle is defined by its bottom left corner and top right corner as shown ... 阅读全文
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要求：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 inte... 阅读全文
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PHP经典面试题：（不断跟进补充中。。。）1、用PHP打印出前一天的时间格式是2009-02-1022:21:21(2分)echodate('Y-m-dH:i:s',strtotime('-1day'));或者$yesterday=time()-(24*60*60);echo'today:'.dat... 阅读全文
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Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-nega... 阅读全文
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Description:Count the number of prime numbers less than a non-negative number,n.本题给定一个非负数n，让我们求小于n的质数的个数，解题方法就在第二个提示埃拉托斯特尼筛法Sieve of Eratosthenes中，这个算... 阅读全文
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Implementatoito convert a string to an integer.Hint:Carefully consider all possible input cases.Notes:It is intended for this problem to be specified ... 阅读全文