Submission #819973

#	Time	Username	Problem	Language	Result	Execution time	Memory
819973		Alan	Strange Device (APIO19_strange_device)	C++17	100 / 100	1544 ms	100096 KiB

strange_device

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const ll inf = 1e18;

void add (set<pair<ll, ll>>& st, ll l, ll r) {
	auto it = st.lower_bound({l, 0}), tmp = it;
	if (it != st.begin() && (--tmp)->second >= l) {
		l = tmp->first;
		r = max(r, tmp->second);
		st.erase(tmp);
	}
	while (it != st.end()) {
		if (r >= it->first) {
			r = max(r, it->second);
			it = st.erase(it);
		} else break;
	}
	st.insert({l, r});
}

int main () {
	ll n, a, b;
	cin >> n >> a >> b;
	ll mod;
	if (a / gcd(a, b+1) > inf / b) mod = inf;
	else mod = a / gcd(a, b+1) * b;
	set<pair<ll, ll>> st;
	while (n--) {
		ll l, r;
		cin >> l >> r;
		if (r-l+1 >= mod) {
			cout << mod << '\n';
			return 0;
		}
		if (l % mod > r % mod) {
			add(st, 0, r % mod);
			add(st, l % mod, mod-1);
		} else add(st, l % mod, r % mod);
	}
	ll ans = 0;
	for (auto& [l, r] : st) ans += r-l+1;
	cout << ans << '\n';
	return 0;
}

• 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