답안 #467993

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
467993	2021-08-25T20:05:01 Z	Rajat850	Job Scheduling (CEOI12_jobs)	C++14	100 / 100	526 ms	26356 KB

jobs

#include <bits/stdc++.h>
using namespace std;

#define all(x) begin(x), end(x)
#define mp make_pair

using pi = pair<int, int>;
using vi = vector<int>;

int N, D, M;

// test if it is possible to finish the jobs using given # of machines
// return: first: possible or not, second: if possible, the schedule for the jobs
pair<bool, vector<vi>> isFeasible(const vector<pi> &jobs, int machineCount)
{
	vector<vi> schedule(N);
	int reqNum = 0;
	// we simulate from day 1 until the last day N
	// we move to the next day if all the machines are used or
	// there is no more job requests left on or before this day
	for (int day = 1; day <= N; day++)
	{
		for (int j = 0; j < machineCount; j++)
		{
			// if all jobs before and on this day are finished,
			// we can go to the next day, even if there are usable machines left
			// we can determine that since the vector jobs is sorted
			if (jobs[reqNum].first > day)
				break;
			// if the current date is before the deadline for the job
			// we can add this job to the schedule and move to the next job request
			if (jobs[reqNum].first + D >= day)
				schedule[day - 1].push_back(jobs[reqNum++].second);
			// otherwise, it is not feasible due to deadline
			else
				return mp(false, schedule);

			// if we have processed all the requests, we have found a feasible sol
			if (reqNum == M)
				return mp(true, schedule);
		}
	}
	// if not all the requests can be processed within the given N days,
	// then it is not feasible
	return mp(false, schedule);
}

int main()
{
	cin.tie(0)->sync_with_stdio(false);

	cin >> N >> D >> M;
	vector<pi> jobs(M);
	for (int i = 0; i < M; i++)
	{
		int day;
		cin >> day;
		// first: request date, second: index [1..M]
		jobs[i] = mp(day, i + 1);
	}
	// we sort the jobs by the request date in ascending order
	// sothat we can test them using isFeasible() in linear time whether they
	// can be done in given time using a certain amount of machines
	sort(all(jobs));

	vector<vi> result;
	// binary search on the number of machines for the minimum possible solution
	// left and right bound, l and r
	int l = 1, r = M;
	while (l < r)
	{
		int machineNum = (l + r) / 2;
		// test if the jobs would finish within the deadline
		// using the current # of machines, machineNum
		pair<bool, vector<vi>> curResult = isFeasible(jobs, machineNum);
		// if it's possible, we set the right bound as the tested machine number
		// and save the current schedule
		if (curResult.first)
		{
			r = machineNum;
			result = curResult.second;
		}
		// otherwise, we set the left bound to be the tested number + 1
		// and test the next machineNum again
		else
			l = machineNum + 1;
	}

	cout << l << "\n";
	for (int i = 0; i < N; i++)
	{
		for (int &idx : result[i])
			cout << idx << " ";
		cout << 0 << "\n";
	}
}

Subtask #1

100.0 / 100.0

#	결과	실행 시간	메모리	Grader output
1	Correct	38 ms	2960 KB	Output is correct
2	Correct	39 ms	3052 KB	Output is correct
3	Correct	38 ms	2980 KB	Output is correct
4	Correct	40 ms	2948 KB	Output is correct
5	Correct	38 ms	2960 KB	Output is correct
6	Correct	38 ms	2952 KB	Output is correct
7	Correct	39 ms	3020 KB	Output is correct
8	Correct	38 ms	2960 KB	Output is correct
9	Correct	95 ms	9672 KB	Output is correct
10	Correct	95 ms	9684 KB	Output is correct
11	Correct	47 ms	2732 KB	Output is correct
12	Correct	100 ms	4904 KB	Output is correct
13	Correct	138 ms	8504 KB	Output is correct
14	Correct	252 ms	10828 KB	Output is correct
15	Correct	246 ms	10956 KB	Output is correct
16	Correct	360 ms	16092 KB	Output is correct
17	Correct	386 ms	18792 KB	Output is correct
18	Correct	402 ms	23400 KB	Output is correct
19	Correct	526 ms	26356 KB	Output is correct
20	Correct	396 ms	18720 KB	Output is correct