[BZOJ1572] [Usaco2009 Open]工作安排Job（贪心 + 堆）

Posted 2020-10-06 蒟蒻zht的博客

传送门

 

把任务按照d排序

一次加入到堆中，如果当前放不进堆中，并且比堆中最小的大，

就从堆中弹出一个数，再把当前的数放进去

 

#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define N 100001
#define LL long long

using namespace std;

int n;
LL ans;
priority_queue <LL, vector <LL>, greater <LL> > q;

struct node
{
	LL d, p;
}a[N];

inline LL read()
{
	LL x = 0, f = 1;
	char ch = getchar();
	for(; !isdigit(ch); ch = getchar()) if(ch == ‘-‘) f = -1;
	for(; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + ch - ‘0‘;
	return x * f;
} 

inline bool cmp(node x, node y)
{
	return x.d < y.d;
}

int main()
{
	int i, now = 0;
	n = read();
	for(i = 1; i <= n; i++)
		a[i].d = read(), a[i].p = read();
	sort(a + 1, a + n + 1, cmp);
	for(i = 1; i <= n; i++)
		if(q.size() < a[i].d) q.push(a[i].p);
		else if(!q.empty() && a[i].p > q.top())
		{
			q.pop();
			q.push(a[i].p);
		}
	while(!q.empty()) ans += q.top(), q.pop();
	printf("%lld\n", ans);
	return 0;
}