hdu 3280 动态规划

思路：dp[i][j]表示区间i,j变为回文串最少的代价.

#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<cstdio>
#include<vector>
#include<string>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#define pb push_back
#define mp make_pair
#define Maxn 2002
#define Maxm 80002
#define LL __int64
#define Abs(x) ((x)>0?(x):(-x))
#define lson(x) (x<<1)
#define rson(x) (x<<1|1)
#define inf 0x7fffffff
#define Mod 1000000007
using namespace std;
int dp[Maxn][Maxn],val[255];
char str[Maxn];
int main()
{
    int n,m,i,j,a,b;
    char s[5];
   while(scanf("%d%d",&n,&m)!=EOF){
    scanf("%s",str+1);
    for(i=1;i<=n;i++){
        scanf("%s %d %d",s,&a,&b);
        val[s[0]]=min(a,b);
    }
    for(i=1;i<=m;i++){
        for(j=i-1;j>=1;j--){
            if(str[i]==str[j]){
                dp[j][i]=dp[j+1][i-1];
            }
            else{
                dp[j][i]=min(dp[j+1][i]+val[str[j]],dp[j][i-1]+val[str[i]]);
            }
        }
    }
    printf("%d\n",dp[1][m]);
   }
    return 0;
}