#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<queue>
#include<vector>
#include<set>
using namespace std;
int n,dp[2][5010];
char s1[5010],s2[5010];
int main()
{
while(scanf("%d",&n)!=EOF)
{
getchar();
scanf("%s",s1);
for(int i=0;i<n;i++)
s2[i]=s1[n-i-1];
memset(dp,0,sizeof(dp));
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
{
if(s1[i-1]==s2[j-1])
{
dp[i%2][j]=dp[(i-1)%2][j-1]+1;
}
else
dp[i%2][j]=max(dp[(i-1)%2][j],dp[i%2][j-1]);
}
printf("%d\n",n-dp[n%2][n]);
}
return 0;
}
|
关于HDU-ACM集训队选拔以及HDU12月份校赛的安排 【比赛提醒】BestCoder 你报名了吗？（点击报名） 【科普】什么是BestCoder？如何参加？ |
PalindromeTime Limit: 4000/2000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Problem 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 Sample Output 2 Source Recommend linle |