Submission #410630

#	Time	Username	Problem	Language	Result	Execution time	Memory
410630		dynam1c	Strange Device (APIO19_strange_device)	C++17	0 / 100	1 ms	204 KiB

strange_device

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

#define endl "\n"
#define all(c) (c).begin(),(c).end()

// when you ponder, divide and conquer

#define lo __int128

lo _gcd(lo x, lo y) {
	if (x == 0) return y;
	return _gcd(y % x, x);
}

signed main() {
	// freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	
	ll n, a, b;
	cin >> n >> a >> b;
	lo g = _gcd(b+1, (lo) a*b);
	lo m = (lo) a * b / g;
	vector<pair<lo, int>> evs;
	for (int i = 0; i < n; i++) {
		ll xl, xr;
		cin >> xl >> xr;
		xr++;
		lo l = xl % m;
		lo r = xr % m;
		if (r < l)
			evs.emplace_back(0, -1), evs.emplace_back(r, 1), evs.emplace_back(l, -1), evs.emplace_back(m, 1);
		else
			evs.emplace_back(l, -1), evs.emplace_back(r, 1);
	}
	sort(all(evs));
	ll res = 0;
	lo p = 0;
	int c = 0;
	for (auto [x, t] : evs) {
		if (c == 0) p = x;
		c -= t;
		if (c == 0) res += x-p;
	}
	cout << res << endl;
}
/* --- PSolving ---
 * Simplifying (getting rid of variables, conditions, code logic, etc.)
 * Reframing
 * Solving a subtask (subgoal, aux. problem, removing a condition or fixing a parameter, etc.)
 * Inducing
 * Divide and conquer
 * Working backwards
 * Visual intuition
 * !! Reductions don't have to be specializations, they can be generalizations
 */

• Subtask 1: 0 / 10
• Subtask 2: 0 / 5
• Subtask 3: 0 / 5
• Subtask 4: 0 / 5
• Subtask 5: 0 / 5
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20
• Subtask 8: 0 / 30