Submission #746568

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
746568	2023-05-22T19:33:34 Z	hasan_tawsif	Job Scheduling (CEOI12_jobs)	C++14	100 / 100	485 ms	26888 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

#	Verdict	Execution time	Memory	Grader output
1	Correct	33 ms	3288 KB	Output is correct
2	Correct	41 ms	3304 KB	Output is correct
3	Correct	33 ms	3268 KB	Output is correct
4	Correct	34 ms	3276 KB	Output is correct
5	Correct	32 ms	3304 KB	Output is correct
6	Correct	35 ms	3340 KB	Output is correct
7	Correct	35 ms	3324 KB	Output is correct
8	Correct	41 ms	3268 KB	Output is correct
9	Correct	92 ms	9904 KB	Output is correct
10	Correct	86 ms	9948 KB	Output is correct
11	Correct	56 ms	3144 KB	Output is correct
12	Correct	92 ms	5384 KB	Output is correct
13	Correct	110 ms	8940 KB	Output is correct
14	Correct	221 ms	11308 KB	Output is correct
15	Correct	220 ms	11512 KB	Output is correct
16	Correct	306 ms	16556 KB	Output is correct
17	Correct	356 ms	19324 KB	Output is correct
18	Correct	368 ms	23628 KB	Output is correct
19	Correct	485 ms	26888 KB	Output is correct
20	Correct	357 ms	19408 KB	Output is correct