《LeetBook》leetcode题解(9):Palindrome Number[E]——回文数字

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《LeetBook》leetcode题解(9):Palindrome Number[E]——回文数字

我现在在做一个叫<leetbook>的开源书项目,把解题思路都同步更新到github上了,需要的同学可以去看看地址:https://github.com/hk029/leetcode 这个是书的地址:https://hk029.gitbooks.io/leetbook/ 009. Palindrome Number[E] 问题: Determine whether an integer is a palindrome. Do this without extra space. 思路这里说不…

LeetCode 9. Palindrome Number （回文数字）

Determine whether an integer is a palindrome. Do this without extra space. 题目标签:Math 题目给了我们一个int x, 让我们判断它是不是回文数字. 首先,负数就不是回文数字,因为有个负号. 剩下的都是正数,只要把数字 reverse 一下,和原来的比较,一样就是回文. 当有overflow 的时候,返回一个负数就可以了(因为负数肯定不会和正数相等). Java Solution: Runtime beats 61.…

[LeetCode] Palindrome Number 验证回文数字

Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using ext…

[LeetCode] 9. Palindrome Number 验证回文数字

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanation: From left to right, it reads -121. From right to…

LeetCode 9 Palindrome Number（回文数字判断）

Long Time No See ! 题目链接https://leetcode.com/problems/palindrome-number/?tab=Description 首先确定该数字的位数.按照已知数字x对10进行多次求余运算,可以得到数字位数. 具体思路: 1.每次取出该数字的最高位和最低位进行比较. 2.如果不相等则直接返回FALSE, 3.如果相等修改x的值(去掉最高位也同时去掉最低位)其中去掉最高位可以通过求模运算,去掉最低位可以采用除以10 4.进行循环直到x的值不大于…

Leetcode 9. Palindrome Number(判断回文数字）

Determine whether an integer is a palindrome. Do this without extra space.(不要使用额外的空间) Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using extra space. You…

从0开始的LeetCode生活—9. Palindrome Number（回文数）

题目大意: 判断输入的数字是不是回文数.所谓回文数就是正反读都一样的数字,比如说11,121,1221这样子的数字.负数不会是回文数. 解题思路: 思路一:如果这个数是负数,则返回false,否则用一个变量记录这个数字你转后的数字,判断它和逆转前是否相等. 思路二:如果是负数或者这个数个位为0,则返回false(0除外,如果是0也返回true).否则用一个数字记录它逆转的一半,与其另一半比较,查看是否相等.(考虑数字位数的奇偶性) 解决代码: 我只写了思路二的代码,因为相对思路二的效率比思路一高…

[LeetCode]9. Palindrome Number判断回文数字

/* 查看网上的思路有两种: 1.每次取两边的数,然后进行比较 2.取数的倒置数,进行比较 */ public boolean isPalindrome1(int x) { if (x<0) return false; //以四位数为例,取左边的数用的方法是/1000,取右边的数用的是%10 //注意每次取完两遍要更新数和位数 int len = 1; int temp = x; while (temp>=10) { len*=10; temp/=10; } while (x!=0) { in…

[LeetCode] 409. Longest Palindrome 最长回文

Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters. This is case sensitive, for example "Aa" is not considered a palindrome here. Note:Assume the lengt…

leetcode题解 9. Palindrome Number

9. Palindrome Number 题目: Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the…

[LeetCode 题解]：Palindrome Number

前言 [LeetCode 题解]系列传送门: http://www.cnblogs.com/double-win/category/573499.html 1.题目描述 Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of c…

【LeetCode】9、Palindrome Number（回文数）

题目等级:Easy 题目描述: Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanation: From left to right, it reads -12…

《LeetBook》leetcode题解(5):Longest Palindromic [M]——回文串判断

我现在在做一个叫<leetbook>的免费开源书项目,力求提供最易懂的中文思路,目前把解题思路都同步更新到gitbook上了,需要的同学可以去看看书的地址:https://hk029.gitbooks.io/leetbook/ 005.Longest Palindromic [M] Longest Palindromic M 题目思路题目 Given a string S, find the longest palindromic substring in S. You may assu…

[Leetcode] Palindrome number 判断回文数

Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using ext…

LeetCode OJ Palindrome Number（回文数）

class Solution { public: bool isPalindrome(int x) { ,init=x; ) return true; ) return false; ){ r=r*+init%; init=init/; } if(r==x) return true; else return false; } }; 题目: 判断一个整数是不是回文数,即一个数翻转过来是否跟原来的数仍一样. 需要考虑负数,负数无回文数. 解法: 翻转提供的数字,即123的话,需要翻转为321. 再判…

[LeetCode] 680. Valid Palindrome II 验证回文字符串 II

Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome. Example 1: Input: "aba" Output: True Example 2: Input: "abca" Output: True Explanation: You could delete the character 'c'. N…

【LeetCode】- Valid Palindrome（右回文）

[ 问题: ] Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. 直译:给你一个字符串, 判定它是否是回文(仅仅统计字母.数字.其它字符请忽略). For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car"…

palindrome number（回文数）

Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using extra space. You could also…

LeetCode 125 Valid Palindrome（有效回文）（*）

翻译给定一个字符串.确定它是否是回文的,仅仅考虑当中的数字和字符并忽略其它. 比如. "A man, a plan, a canal: Panama" 是回文的. "race a car" 不是回文的批注: 你是否考虑了字符串可能为空?这样的面试的时候是一个好问题. 对于这问题的意图,我们定义空字符串是回文的. 原文 Given a string, determine if it is a palindrome, considering only alphanu…

9. Palindrome Number[E]回文数

题目 Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example1: Input:121 Output:true Example2: Input:-121 Output:flase Explanation:From left to right, it reads -121. From ri…

LeetCode 9. Palindrome Number（回文数）

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanation: From left to right, it reads -121. From right to…