Submission #496123

#	Time	Username	Problem	Language	Result	Execution time	Memory
496123		aryan12	Strange Device (APIO19_strange_device)	C++17	100 / 100	547 ms	69884 KiB

strange_device

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

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

const int MAXT = 1e18 + 5;

int gcd(int a, int b) {
	if(a % b == 0) {
		return b;
	}
	return gcd(b, a % b);
}

void Solve() {
	int n, a, b;
	cin >> n >> a >> b;
	int repetition = a / gcd(a, b + 1);
	vector<pair<int, int> > v(n + 1);
	int sum = 0;
	for(int i = 1; i <= n; i++) {
		cin >> v[i].first >> v[i].second;
		sum += (v[i].second - v[i].first + 1);
	}
	if(b > MAXT / repetition) {
		cout << sum << "\n";
		return;
	}
	int repetition2 = a / gcd(a, b + 1) * b;
	vector<pair<int, int> > temp;
	for(int i = 1; i <= n; i++) {
		if(v[i].second - v[i].first + 1 >= repetition2) {
			cout << repetition2 << "\n";
			return;
		}
		int startpoint = v[i].first % repetition2;
		int endpoint = v[i].second % repetition2;
		if(startpoint <= endpoint) {
			temp.push_back({startpoint, endpoint});
		}
		else {
			temp.push_back({startpoint, repetition2 - 1});
			temp.push_back({0LL, endpoint});
		}
	}
	sort(temp.begin(), temp.end());
	int ans = 0, left = 0, right = -1;
	for(int i = 0; i < temp.size(); i++) {
		if(temp[i].first > right) {
			ans += (right - left + 1);
			left = temp[i].first;
			right = temp[i].second;
		}
		else {
			right = max(right, temp[i].second);
		}
	}
	ans += (right - left + 1);
	cout << ans << "\n";
}

int32_t main() {
	auto begin = std::chrono::high_resolution_clock::now();
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t = 1;
	//cin >> t;
	while(t--) {
		Solve();
	}
	auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
	return 0;
}

Compilation message (stderr)

strange_device.cpp: In function 'void Solve()':
strange_device.cpp:49:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |  for(int i = 0; i < temp.size(); i++) {
      |                 ~~^~~~~~~~~~~~~

• 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