题解 | #兑换零钱#

#include <algorithm>
#include <cstring>
#include <iostream>
using namespace std;

const int N = 10010;
int f[N], a[N];

int main() {
    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= n; i ++) cin >> a[i];
    memset(f, 0x3f, sizeof f);
    f[0] = 0;
    for(int i = 1; i <= n; i ++)
        for(int j = a[i]; j <= m; j ++)
            f[j] = min(f[j], f[j - a[i]] + 1);
    if(f[m] > 5000) cout << "-1" << endl;
    else cout << f[m] << endl;
    return 0;
}