POJ:http://poj.org/problem?id=2402 LA:https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=890 题目大意: 回文数从小到大排列为:1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, --输入n,(1<=n<=2*10^9),求第n小的回文数. 思路: 我…
题目链接:http://poj.org/problem?id=3974 题意:求一给定字符串最长回文子串的长度 思路:直接套模板manacher算法 code: #include <cstdio> #include <cstring> #include <algorithm> using namespace std; ; *MAXN]; *MAXN]; void Manacher(char s[], int len) { ; Ma[l++] = 'S'; Ma[l++]…
题目链接 水题,LA我居然没找到在那里. #include <cstdio> #include <cstring> #include <string> #include <cmath> #include <ctime> #include <cstdlib> #include <iostream> using namespace std; #define LL long long LL dp[],bin[]; ],s; vo…
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 -121. From rig…
题目链接: http://poj.org/problem?id=2402 题目大意就是让你找到第n个回文数是什么. 第一个思路当然是一个一个地构造回文数直到找到第n个回文数为止(也许大部分人一开始都是这样的思路). 很明显找到第n个之前的所有操作都是浪费, 这也是这个方法的最大弱点. 抱着侥幸心理(谁知道数据弱不弱啊)用这种方法提交了下, TLE (在另一个OJ上提交是9个测试点过了6个). 第二个思路也很容易想到, 但是比第一个思路要麻烦: 第n个回文数的每位数字都与n有一定的关联. 也就是说…
问题 给一个数k,给出第k个回文数  链接 题解 打表找规律,详见https://www.cnblogs.com/lfri/p/10459982.html,差别仅在于这里从1数起. AC代码 #include<cstdio> #include<iostream> #include<string> #include<sstream> using namespace std; typedef long long LL; void solve(string str…
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…
Find the largest palindrome made from the product of two n-digit numbers. Since the result could be very large, you should return the largest palindrome mod 1337. Example: Input: 2 Output: 987 Explanation: 99 x 91 = 9009, 9009 % 1337 = 987 Note: The…
题目描述: Find the largest palindrome made from the product of two n-digit numbers. Since the result could be very large, you should return the largest palindrome mod 1337. Example: Input: 2 Output: 987 Explanation: 99 x 91 = 9009, 9009 % 1337 = 987 Note…
文章转自http://blog.163.com/hljmdjlln@126/blog/static/5473620620120412525181/ 做LC上的题"Palindrome number"时翻到此文章,经过少量修改后如下. 回文数是数学界中的一种有趣的现象.比如121就是一个回文数.回文数的数字互相对应,从中间一个任意一位数字起,左右每隔一个的数字都相等.回文数有许多神奇的规律和奥秘.主要分为读数回文数.平方回文数.乘积回文数以及倒乘回文数. 一.读数回文数 [解释]读数回文…
Valid Palindrome回文数 whowhoha@outlook.com Question: 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"…
回文数,从前到后,从后到前都一样 把数字转成字符串来处理 package com.rust.cal; public class Palindrome { public static boolean isPalindrome(int x) { String s = String.valueOf(x); String revers = new StringBuffer(s).reverse().toString(); if (s.equalsIgnoreCase(revers)) { return…
Problem: Determine whether an integer is a palindrome. Do this without extra space. 简单的回文数,大一肯定有要求写过,不过从基础开始尝试吧. Solution: public class Solution { public boolean isPalindrome(int x) { int n=1; int copyx=x; if(x<0)return false; if(x<10)return true; w…
Given an integer n, find the closest integer (not including itself), which is a palindrome. The 'closest' is defined as absolute difference minimized between two integers. Example 1: Input: "123" Output: "121" Note: The input n is a po…
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…
Find the smallest prime palindrome greater than or equal to N. Recall that a number is prime if it's only divisors are 1 and itself, and it is greater than 1.  For example, 2,3,5,7,11 and 13 are primes. Recall that a number is a palindrome if it read…
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…
Given an integer n, find the closest integer (not including itself), which is a palindrome. The 'closest' is defined as absolute difference minimized between two integers. Example 1: Input: "123" Output: "121"  Note: The input n is a p…
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…
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 converting the integer to string, note the restriction of using extra space. You could a…
文章转自http://blog.163.com/hljmdjlln@126/blog/static/5473620620120412525181/ 做LC上的题"Palindrome number"时翻到此文章,经过少量修改后如下. 回文数是数学界中的一种有趣的现象.比如121就是一个回文数.回文数的数字互相对应,从中间一个任意一位数字起,左右每隔一个的数字都相等.回文数有许多神奇的规律和奥秘.主要分为读数回文数.平方回文数.乘积回文数以及倒乘回文数. 一.读数回文数 [解释]读数回文…
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…
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…
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…
作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 公众号:负雪明烛 本文关键词:回文数,回文,题解,Leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 判断回文字符串 翻转数字 日期 题目地址:https://leetcode.com/problems/palindrome-number/#/description 题目描述 Determine whether an integer is…
题目意思:判断是否为回文数,不许使用额外空间 ps:一直不理解额外空间的意思,int能用吗 思路:1.比较头尾 2.翻转,越界问题需考虑 class Solution { public: bool isPalindrome(int x) { )return false; )return true; ,temp=x; while(temp){ num++; temp=temp/; } while(x){ start=x/,num-)); end=x%; if(start!=end)return f…
判断一个数字是否是回文数,尝试不用其他额外空间. 注意: 负数也有可能成为回文数吗? 如果你想让int转为string,注意不用其他空间这个约束. 你也可以翻转一个int,但是有可能会溢出.     public class Solution { public boolean isPalindrome(int x) { if(x<0) return false; int temp = x, reverseX = 0; while (temp > 0) { reverseX = reverseX…
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…
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…
判断一个整数是否是回文数.回文数是指正序(从左向右)和倒序(从右向左)读都是一样的整数. 示例 1: 输入: 121 输出: true 示例 2: 输入: -121 输出: false 解释: 从左向右读, 为 -121 . 从右向左读, 为 121- .因此它不是一个回文数. 示例 3: 输入: 10 输出: false 解释: 从右向左读, 为 01 .因此它不是一个回文数. 进阶: 你能不将整数转为字符串来解决这个问题吗? 要求不能转化为字符串用reverse直接反转: 基本思路: 负数不…