Submission #196918

#	Time	Username	Problem	Language	Result	Execution time	Memory
196918		tincamatei	Strange Device (APIO19_strange_device)	C++14	100 / 100	1503 ms	100272 KiB

strange_device

#include <bits/stdc++.h>

using namespace std;

const long long INF = 1LL << 62;

long long gcd(long long a, long long b) {
	long long r;
	while(b > 0) {
		r = a % b;
		a = b;
		b = r;
	}
	return a;
}

set<pair<long long, long long> > ranges;

long long insertRange(long long a, long long b) {
	set<pair<long long, long long> >::iterator it;

	it = ranges.lower_bound(make_pair(a, -INF));

	if(it != ranges.begin()) {
		set<pair<long long, long long> >::iterator it2;
		it2 = it;
		it2--;

		if(it2->second >= a) {
			it--;
			a = it->first;
		}
	}
	
	long long rez = 0LL;
	vector<pair<long long, long long> > toErase;
	while(it != ranges.end() && it->first <= b) {
		toErase.push_back(*it);
		rez = rez - (it->second - it->first + 1);
		b = max(b, it->second);
		it++;
	}

	for(auto it: toErase)
		ranges.erase(it);
	ranges.insert(make_pair(a, b));
	rez = rez + b - a + 1;
	
	return rez;
}

int main() {
	int n;
	long long A, B, loopSize, xSkip, convolutions;

	scanf("%d%lld%lld", &n, &A, &B);
	xSkip = B % A + 1;
	convolutions = A / gcd(A, xSkip);

	if(convolutions <= INF / B)
		loopSize = B * convolutions;
	else
		loopSize = INF;

	long long rez = 0LL;
	for(int i = 0; i < n; ++i) {
		long long l, r;
		scanf("%lld%lld", &l, &r);
		
		if(r - l + 1 >= loopSize)
			rez = rez + insertRange(0, loopSize - 1);
		else {
			l = l % loopSize;
			r = r % loopSize;

			if(r >= l)
				rez = rez + insertRange(l, r);
			else {
				rez = rez + insertRange(0, r) +
				            insertRange(l, loopSize - 1);
			}
		}
	}

	printf("%lld\n", rez);

	return 0;
}

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:56:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%lld%lld", &n, &A, &B);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:68:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld", &l, &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