天梯赛 L2-003 月饼

按照月饼的单价排序，使用sort，重载<即可。

#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
typedef long long ll;
const int N = 510;
const int mod = 998244353;
struct box{
	double x,y;
	bool operator<(const box &t) const{
		//y1/x1 > y2/x2
		return y * t.x > t.y * x; //判断单价
	}
};
void solve() {
	int n,d;
	cin>>n>>d;
	vector<box> a(n+1);
	for(int i = 1 ; i <= n ; i++){
		cin>>a[i].x;
	}
	for(int i = 1 ; i <= n ; i++){
		cin>>a[i].y;
	}
	sort(a.begin()+1,a.end());
	double ans = 0.0;
	double sy = d;
	for(int i = 1 ; i <= n ; i++){
		double need = min(a[i].x,sy);
		ans += need * 1.0 * a[i].y / a[i].x;
		sy -= need;
		if(sy <= 0){
			break;
		}
	}
	printf("%.2lf",ans);
}
signed main() {
    // ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int tt = 1;
    //    cin >> tt;
    while (tt--) {
        solve();
    }
    return 0;
}