代码语言：javascript复制
#include<bits/stdc .h>
#define mem(a,b) memset(a,b,sizeof(a))
#define ll long long
using namespace std;
#define N 300005
struct node
{
ll x,y;
} se[N];
bool cmp(node a,node b)
{
return a.y>b.y;
}
int main()
{
ll n,m;
scanf("%lld%lld",&n,&m);
priority_queue<ll,vector<ll>,greater<ll> >q;
ll sum=0;
ll ans=0;
for(ll i=0; i<n; i )
{
scanf("%lld%lld",&se[i].x,&se[i].y);
}
sort(se,se n,cmp);//因为乘se[i].b，所以先对其排序
for(int i=0; i<n; i )
{
q.push(se[i].x);
sum =se[i].x;
if(q.size()>m)
{//首先不能保证前m乘积个一定最大，
sum-=q.top();
q.pop();
}
ans=max(ans,sum*se[i].y);
// printf("%lld*******n",ans);
}
printf("%lldn",ans);
return 0;
}
