struct node{

int milk,money;

};

node a[2000000];

bool cmp(node a, node b){

return a.money<b.money;

}

int main()

{

int tot,n;

cin>>tot>>n;

for(int i=1;i<=n;i++){

cin>>a[i].money>>a[i].milk;

}

sort(a+1, a+n+1, cmp);

int ans=0;

for(int i=1;i<=n;i++){

if(tot<a[i].milk){

ans+=tot*a[i].money;

break;

}

else{

tot-=a[i].milk;

ans+=a[i].milk*a[i].mone y;

}

}

cout<<ans<<endl;

答案已提交，得分100分，可放心参考❤️

我是 Adydv，可以给个好评吗，谢谢啦❤️

#include<bits/stdc++.h>
using namespace std;
//输入保证正确
//输出看仔细
//所有情况都测
//数组定义，保证正确
int n, m;
struct milk{
    int p,a;
}c[5005];
bool cmp(milk x,milk y){
    return x.p<y.p;
}
int main()
{
	cin>> n>> m;
	for( int i = 1; i <= m; i ++)
	{
		 cin >> c[i].p>> c[i].a ;
	}
	sort(c+1,c+m+1,cmp);
//	for( int i = 1; i <= m; i ++)
//	{
//		 cout << c[i].p<<" "<< c[i].a <<" ";
//	}
	int sum = 0 ;
	for( int i = 1; i <= m; i ++)
	{
		if(n >= c[i].a)
		{
			n -= c[i].a ;
			sum += c[i].p * c[i].a ;
		}
		else
		{
			sum += n * c[i].p ;
			break;
		}
	}
	cout << sum;
 	return 0;
}