poj3280

dp

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#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

using namespace std;



#define maxn 205

#define maxm 2005

#define inf 0x3f3f3f3f



int n, m;

char st[maxm];

int cost[maxn];

int f[maxm][maxm];



void input()

{

    scanf("%d%d", &n, &m);

    scanf("%s", st + 1);

    for (int i = 0; i < n; i++)

    {

        char ch[5];

        int a, b;

        scanf("%s%d%d", ch, &a, &b);

        cost[(int)ch[0]] = min(a, b);

    }

}



int work()

{

    // f[i][j] = min(f[i - 1][j] + cost[i], f[i][j + 1] + cost[j])

    // f[i][j] = f[i - 1][j + 1]

    f[0][m + 1] = 0;

    for (int i = m; i > 0; i--)

        f[0][i] = cost[(int)st[i]] + f[0][i + 1];

    for (int i = 1; i <= m; i++)

        f[i][m + 1] = f[i - 1][m + 1] + cost[(int)st[i]];

    for (int i = 1; i < m; i++)

    {

        for (int j = m; j > i; j--)

        {

            f[i][j] = min(f[i - 1][j] + cost[(int)st[i]], f[i][j + 1]

                    + cost[(int)st[j]]);

            if (st[i] == st[j])

                f[i][j] = min(f[i][j], f[i - 1][j + 1]);

        }

    }

    int ret = inf;

    for (int i = 1; i <= m; i++)

        ret = min(ret, f[i - 1][i + 1]);

    for (int i = 1; i < m; i++)

        ret = min(ret, f[i][i + 1]);

    return ret;

}



int main()

{

    //freopen("t.txt", "r", stdin);

    input();

    printf("%d\n", work());

    return 0;

}