HDU_2019 选课时间(题目已修改,注意读题)(生成函数)

　　貌似跟1171一样的，呃。。。

My Code:

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

const int N = 100;

struct node {
    int val;
    int num;
} a[55];

int c1[N], c2[N];


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

    int t, n, i, j, sum, k, m;
    while(cin >> t) {
        while(t--) {
            scanf("%d%d", &n, &m);
            for(i = 1; i <= m; ++i) {
                scanf("%d%d", &a[i].val, &a[i].num);
            }
            for(i = 0; i <= n; i++) {
                c1[i] = 1; c2[i] = 0;
            }
            sum = a[1].val * a[1].num;
            for(i = 2; i <= m; ++ i) {
                for(j = 0; j <= n && j <= sum; ++ j) {
                    for(k = 0; k + j <= n && k <= a[i].val * a[i].num; k += a[i].val) {
                        c2[k+j] += c1[j];
                    }
                }
                sum += a[i].val * a[i].num;
                for(j = 0; j <= sum && j <= n; ++ j) {
                    c1[j] = c2[j]; c2[j] = 0;
                }
            }
            printf("%d\n", c1[n]);
        }
    }
    return 0;
}