hdu 2159 FATE 二维费用的完全背包

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <stack>
#include <set>
#include <queue>
#include <vector>

using namespace std;

typedef long long ll;

const int maxn = 130;
const int INF = 100000;

int a[maxn], b[maxn];
int dp[maxn][maxn];

int main()
{
    //freopen("in.txt", "r", stdin);

    int n, m, k, s;
    while(scanf("%d%d%d%d", &n, &m, &k, &s) == 4)
    {
        for(int i = 1; i <= k; i++)
            scanf("%d%d", &a[i], &b[i]);

        int V = n + 20;
        int ans = INF;

        for(int i = 0; i <= n + 20; i++)
            for(int j = 0; j <= s; j++)
                dp[i][j] = INF;
        dp[0][0] = 0;

        for(int z = 1; z <= k; z++)
            for(int i = a[z]; i < V; i++)
                for(int j = 1; j <= s; j++)
                {
                    dp[i][j] = min(dp[i][j], dp[i - a[z]][j - 1] + b[z]);
                    if(i >= n && dp[i][j] <= m && dp[i][j] < ans)
                        ans = dp[i][j];
                }

        if(ans == INF)
            printf("-1\n");
        else
            printf("%d\n", m - ans);

    }


    return 0;
}