zoukankan      html  css  js  c++  java
  • [POJ] Palindrome

    Palindrome
    Time Limit: 3000MS   Memory Limit: 65536K
    Total Submissions: 62102   Accepted: 21643

    Description

    A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a program which, given a string, determines the minimal number of characters to be inserted into the string in order to obtain a palindrome. 

    As an example, by inserting 2 characters, the string "Ab3bd" can be transformed into a palindrome ("dAb3bAd" or "Adb3bdA"). However, inserting fewer than 2 characters does not produce a palindrome. 

    Input

    Your program is to read from standard input. The first line contains one integer: the length of the input string N, 3 <= N <= 5000. The second line contains one string with length N. The string is formed from uppercase letters from 'A' to 'Z', lowercase letters from 'a' to 'z' and digits from '0' to '9'. Uppercase and lowercase letters are to be considered distinct.

    Output

    Your program is to write to standard output. The first line contains one integer, which is the desired minimal number.

    Sample Input

    5
    Ab3bd

    Sample Output

    2

    本题是一个求LCS长度的问题,具体算法及思路可以参考

    http://blog.csdn.net/v_july_v/article/details/6695482

    注意用int会爆空间

    #include<iostream>
    using namespace std;
    
    short c[5005][5005];
    char s[5005];
    
    int main()
    {
    	int n;
    	cin>>n;
    
    	for(int i=1;i<=n;i++)
    	{
    		cin>>s[i];
    	}
        
    	for(int i=0;i<=n;i++)
    		c[i][0]=c[0][i]=0;
    
        for(int i=1;i<=n;i++)
        	for(int j=1;j<=n;j++)
        	{
        		if(s[i]==s[n-j+1])
        			c[i][j]=c[i-1][j-1]+1;
        		else if(c[i-1][j]>=c[i][j-1])
        			c[i][j]=c[i-1][j];
        		else
        			c[i][j]=c[i][j-1];
        	}
    
        cout<<n-c[n][n]<<endl;
    
        return 0;
    }
    

      

  • 相关阅读:
    SVN: repository browser 库浏览器
    创业泡沫真他妈的大出血来了 --个人需要创业以谋生,行业需要创业以求变,国家需要创业以维稳
    判断输入的是否是大于0的正整数
    linux开放或限制端口和ip访问
    linux模糊删除es索引脚本
    ssh免密登录
    DES加密解密
    SpringBoot 单元测试
    SpringContextHolder 工具类
    fiddler抓包 443 请求不到数据
  • 原文地址:https://www.cnblogs.com/KennyRom/p/6486934.html
Copyright © 2011-2022 走看看