01背包

注意的求的内容是恰好装满且求最小价值，所以需要初始化其数据为 inf。

注意输出的最后有小数点。

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int inf = 0x3f3f3f3f, MOD = 1E9 + 7;
const int N = 505, M=1e5+5;
int n,m,w[N],v[N],a,b,f[M];
void solve() {
    cin >> a >> b >> n;
    for (int i = 1; i <= n; i++) cin >> w[i] >> v[i];
    m = b - a;
    memset(f, 0x3f, sizeof f);
    f[0] = 0;
    for (int i = 1; i <= n; i++)
        for (int j = v[i]; j <= m; j++)
            f[j] = min(f[j], f[j - v[i]] + w[i]);
    if (f[m] >= inf) cout << "This is impossible.\n";
    else cout << "The minimum amount of money in the piggy-bank is " << f[m] <<"."<< endl;
}
int main(int argc, char* argv[]) {
    int T = 1; cin >> T;
    while (T--) solve();
    return 0;
}