JZOJ 5849 d

Description

Input

Output

Data Constraint

做法：考虑贪心使得mina*minb最大，先以a为关键字排序，然后枚举删除最小的0~m个ai，对应删除最小的bi，然后更新答案。

 #include <cstdio>
 #include <cstring>
 #include <iostream>
 #include <queue>
 #include <algorithm>
 #define M 100007
 #define LL long long
 #define rep(i,a,b) for(int i=a;i<=b;i++)
 using namespace std;
 int T,n,m;
 LL ans;
 struct arr{
     int a,b,site;
 }f[M];
 bool v[M];

 LL max(LL a,LL b) {return a>b?a:b;}

 int Cmp(arr x,arr y){
     return x.a<y.a;
 }

 bool operator <(const arr &x,const arr &y){
     return x.b>y.b;
 }

 void Init(){
     memset(f,,sizeof(f));
     scanf("%d%d",&n,&m);
     rep(i,,n)    scanf("%d%d",&f[i].a,&f[i].b),f[i].site=i;
     sort(+f,f+n+,Cmp);
 }

 void Work(){
     priority_queue<arr> q;
     ans=;
     rep(i,m+,n) q.push(f[i]);
     arr now=q.top();
     ans=max(ans,(LL)f[m+].a*now.b);
     for(int i=m;i>=;i--){
         q.pop();
         q.push(f[i]);
         now=q.top();
         ans=max(ans,(LL)f[i].a*now.b);
     }
     now=q.top();
     ans=max(ans,(LL)f[].a*now.b);
     printf("%lld\n",ans);
 }

 int main() {
     freopen("d.in","r",stdin);
     freopen("d.out","w",stdout);
     scanf("%d",&T);
     for(;T--;){
         Init();
         Work();
     }
 }