poj 1159 dp回文串

题意：添加最少的字符使之成为回文串
 1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<queue>
 7 using namespace std;
 8 const int maxn=5001;
 9 int n,m,t;
10 short dp[maxn][maxn];
11 char s[maxn];
12 int main()
13 {
14     int i,j,k;
15     #ifndef ONLINE_JUDGE
16     freopen("1.in","r",stdin);
17     #endif
18         int len=0;
19         scanf("%d",&len);
20         scanf("%s",s);
21         for(i=0;i<len;i++)  dp[i][i]=0;
22         for(k=1;k<len;k++)
23         {
24             for(i=0;i+k<=len;i++)
25             {
26                 int j=k+i;
27                 if(s[i]==s[j])  dp[i][j]=dp[i+1][j-1];
28                 else dp[i][j]=min(dp[i+1][j],dp[i][j-1])+1;
29             }
30         }
31         printf("%d
",dp[0][len-1]);
32     return 0;
33 }