P1208 [USACO1.3] 混合牛奶 Mixing Milk

我的code

#include<bits/stdc++.h>
//#define ?
#define endl "\n"
#define Fc ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define ll long long
#define maxn 5005
using namespace std;

int n, m;
struct nodo {
	int mk;
	int fm;
} a[maxn];
bool cmp(nodo x, nodo y) {
	if (x.mk != y.mk)return x.mk < y.mk;
	else return x.fm > y.fm;
}
int cnt = 1;
int ans;

int main() {

	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);

	Fc;
	cin >> n >> m;
	for (int i = 1; i <= m; ++i) {
		cin >> a[i].mk >> a[i].fm;
	}
	sort(a + 1, a + m + 1, cmp);
	while (n) {
		if (a[cnt].fm != 0) {
			a[cnt].fm--;
			ans += a[cnt].mk;
			n--;
		} else {
			cnt++;
		}
	}
	cout << cnt;
	return 0;
}