|洛谷|堆|P3045 [USACO12FEB]牛券Cow Coupons

来源：互联网发布：最难就业的专业知乎编辑：程序博客网时间：2024/06/05 16:28

https://www.luogu.org/problem/show?pid=3045

把c作为关键字放入一个小根堆，在堆里买k个牛，然后再把这个小根堆里的牛放到另一个以p作为关键字的小根堆，买牛直到没钱

注意m要long long

#include<cstdio>#include<algorithm>#include<cstring>#include<queue>#define ms(i,j) memset(i,j, sizeof i);using namespace std;int n,k;long long m,ans = 0;struct cow{       int p,c;};struct cmp1{       bool operator()(cow a, cow b)       {            return a.c>b.c;       }};struct cmp2{       bool operator()(cow a, cow b)       {            return a.p>b.p;       }};priority_queue<cow, vector<cow>, cmp1> p1;priority_queue<cow, vector<cow>, cmp2> p2;int main(){   scanf("%d%d%lld", &n, &k ,&m);   for (int i=1;i<=n;i++)   {       cow c;       scanf("%d%d", &c.p, &c.c);       p1.push(c);   }   while (k>0&&!p1.empty())   {         if (m-p1.top().c>=0)         {            m -= p1.top().c; p1.pop(); ans++; k--;         } else break;   }   while (!p1.empty()) {p2.push(p1.top()); p1.pop();   }      while (!p2.empty())   {         if (m-p2.top().p>=0)         {            m -= p2.top().p; p2.pop(); ans++;         } else break;   }   printf("%lld\n", ans);   system("pause");    return 0;}

0 0