链接:http://acm.hdu.edu.cn/showproblem.php?pid=4310

 

按比值排序:dps/hp...为了避免小数出现cmp函数写成相乘的形式

 

 

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

class hero
{
public:
    int hp;
    int dps;
};
//按dps/hp排序
bool cmp(hero a,hero b)
{
    return a.dps*b.hp>b.dps*a.hp;
}
int main()
{
    int n;
    int ans;
    int sum;
    hero data[25];
    while(cin>>n)
    {
        ans=0;
        sum=0;
        for(int i=0;i<n;i++)
        {
            cin>>data[i].dps>>data[i].hp;
            sum+=data[i].dps;
        }
        sort(data,data+n,cmp);
        for(int i=0;i<n;i++)
        {
            ans+=sum*data[i].hp;
            sum-=data[i].dps;
        }
        cout<<ans<<endl;

    }
    return 0;
}