南阳理工OJ_题目1023 还是回文

#include <iostream>
#include <cstring>

using namespace std;

int dp();

char ch[2010];
int d[2010][2010];
int m, n;
int cost_add['z'+2];
int cost_sub['z'+2];

int main()
{
    while(cin >> n >> m)
    {
        cin >> (ch+1);
        for(int i = 1; i <= n; i++)
        {
            char c;
            cin >> c;
            cin >> cost_add[c] >> cost_sub[c];
        }
        cout << dp() << '\n';
    }
}

int dp()
{
    int i = 1;
    int j = m;
    memset(d, 0, sizeof(d));
    for(int i = m; i >= 1; i--)
        for(int j = i; j<= m; j++)
        {
            if(ch[i] == ch[j])
                d[i][j] = d[i+1][j-1];
            else
            {
                int t1, t2;
                t1 = d[i+1][j] + min(cost_add[ ch[i] ], cost_sub[ ch[i] ]);
                t2 = d[i][j-1] + min(cost_add[ ch[j] ], cost_sub[ ch[j] ]);
                d[i][j] = min(t1, t2);
            }
        }
    return d[1][m];
}