CodeForces 747C Servers(优先队列)

本文详细解析了Codeforces平台上的C题“Servers”,介绍了如何通过维护最小堆来解决任务分配问题,确保服务器能在特定时间内完成任务。

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题目链接:http://codeforces.com/problemset/problem/747/C点击打开链接


C. Servers
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

There are n servers in a laboratory, each of them can perform tasks. Each server has a unique id — integer from 1 to n.

It is known that during the day q tasks will come, the i-th of them is characterized with three integers: ti — the moment in seconds in which the task will come, ki — the number of servers needed to perform it, and di — the time needed to perform this task in seconds. All ti are distinct.

To perform the i-th task you need ki servers which are unoccupied in the second ti. After the servers begin to perform the task, each of them will be busy over the next di seconds. Thus, they will be busy in seconds ti, ti + 1, ..., ti + di - 1. For performing the task, ki servers with the smallest ids will be chosen from all the unoccupied servers. If in the second ti there are not enough unoccupied servers, the task is ignored.

Write the program that determines which tasks will be performed and which will be ignored.

Input

The first line contains two positive integers n and q (1 ≤ n ≤ 1001 ≤ q ≤ 105) — the number of servers and the number of tasks.

Next q lines contains three integers each, the i-th line contains integers tiki and di (1 ≤ ti ≤ 1061 ≤ ki ≤ n1 ≤ di ≤ 1000) — the moment in seconds in which the i-th task will come, the number of servers needed to perform it, and the time needed to perform this task in seconds. The tasks are given in a chronological order and they will come in distinct seconds.

Output

Print q lines. If the i-th task will be performed by the servers, print in the i-th line the sum of servers' ids on which this task will be performed. Otherwise, print -1.

Examples
input
4 3
1 3 2
2 2 1
3 4 3
output
6
-1
10
input
3 2
3 2 3
5 1 2
output
3
3
input
8 6
1 3 20
4 2 1
6 5 5
10 1 1
15 3 6
21 8 8
output
6
9
30
-1
15
36
Note

In the first example in the second 1 the first task will come, it will be performed on the servers with ids 12 and 3 (the sum of the ids equals 6) during two seconds. In the second 2 the second task will come, it will be ignored, because only the server 4 will be unoccupied at that second. In the second 3 the third task will come. By this time, servers with the ids 12 and 3 will be unoccupied again, so the third task will be done on all the servers with the ids 123 and 4 (the sum of the ids is 10).

In the second example in the second 3 the first task will come, it will be performed on the servers with ids 1 and 2 (the sum of the ids is 3) during three seconds. In the second 5 the second task will come, it will be performed on the server 3, because the first two servers will be busy performing the first task.


由于n的数据只有100 因此复杂度可为q*nlogn<10^7

用最小堆维护结束之间最小的

然后每次查询将堆里符合条件的都取出来排序找服务器号数最小的进行处理再放回堆里

#include <bits/stdc++.h>
using namespace std;
struct xjy
{
	int num;
	int time;
	bool operator < (const xjy &r)const 
	{
		if(time==r.time)
		{
			return num>r.num;
		}
		return time>r.time;
	}
};
priority_queue<xjy> q;
int cmp1(xjy a,xjy b)
{
	return a.num<b.num;
}
int main()
{
	int n,m;
	cin >> n >> m;
	for(int i=1;i<=n;i++)
	{
		xjy mid;
		mid.num=i;
		mid.time=0;
		q.push(mid);
	}
	for(int i=0;i<m;i++)
	{
		int mid[3];
		cin >> mid[0]  >> mid[1] >> mid[2];
		vector<xjy > re;
		while(!q.empty())
		{
			if(q.top().time<=mid[0])
			{
				re.push_back(q.top());
				q.pop();
			}
			else 
				break;
		}
		if(re.size()>=mid[1])
		{
			int sum=0;
			sort(re.begin(),re.end(),cmp1);
			for(int j=0;j<mid[1];j++)
			{
				sum+=re[j].num;
				re[j].time=mid[0]+mid[2];
			}
			for(int j=0;j<re.size();j++)
				q.push(re[j]);
			cout << sum << endl;
		}
		else 
		{
			cout << "-1" << endl;
			for(int j=0;j<re.size();j++)
				q.push(re[j]);
		}
	}
}


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