Submission #171757

#	Time	Username	Problem	Language	Result	Execution time	Memory
171757		Sensei	Strange Device (APIO19_strange_device)	C++17	100 / 100	689 ms	31508 KiB

strange_device

/*
	DATE:		2019-12-30 11:10:15
	NAME:		
	PROBLEM:	APIO19_strange_device
*/
#include <bits/stdc++.h>

using namespace std;

const int MAXN = 1e6;
const long long LLINF = 1e18 + 100;

class Segment {
public:
	long long l, r;
	Segment() {}
	Segment(long long x, long long y) {
		l = x;
		r = y;
	}
};

long long f(long long x, long long y) {
	if (x / __gcd(x, y + 1) > LLINF / y) {
		return LLINF;
	}

	return x / __gcd(x, y + 1) * y;
}

int main() {
	int n;
	cin >> n;

	long long A, B;
	cin >> A >> B;

	long long C = f(A, B);

	vector<Segment> segments;

	for (int i = 1; i <= n; i++) {
		Segment segment;
		scanf("%lld %lld", &segment.l, &segment.r);

		if (segment.r - segment.l + 1 >= C) {
			cout << C << "\n";
			return 0;
		}

		segment.l %= C;
		segment.r %= C;

		if (segment.l <= segment.r) {
			segments.push_back(segment);
		}
		else {
			segments.push_back(Segment(0, segment.r));
			segments.push_back(Segment(segment.l, C - 1));
		}
	}

	sort(segments.begin(), segments.end(), [](Segment x, Segment y) {
		if (x.l == y.l) {
			return x.r < y.r;
		}

		return x.l < y.l;
	});

	long long lastr = -1;
	long long ans = 0;

	for (int i = 0; i < segments.size(); i++) {
		if (segments[i].l > lastr) {
			lastr = segments[i].l - 1;
		}

		if (segments[i].r > lastr) {
			ans += segments[i].r - lastr;
			lastr = segments[i].r;
		}
	}

	cout << ans << "\n";

	return 0;
}

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:74:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < segments.size(); i++) {
                  ~~^~~~~~~~~~~~~~~~~
strange_device.cpp:44:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld %lld", &segment.l, &segment.r);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20
• Subtask 8: 30 / 30