Submission #275139

#	Time	Username	Problem	Language	Result	Execution time	Memory
275139		wutwere	Lasers (NOI19_lasers)	C++17	100 / 100	486 ms	29304 KiB

lasers

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

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	map<int, int> pref;
	int l, r; cin >> l >> r;
	for (int i = 0; i < r; i++) {
		int x; cin >> x;
		vector<int> vals(x);
		int sum = 0, pos = 0;
		for (int j = 0; j < x; j++) {
			cin >> vals[j];
			sum += vals[j];
		}
		for (int j = 0; j < x; j++) {
			int len = l - sum - pos + vals[j];
			if (vals[j] - (len - vals[j]) > 0) {
				pref[l - sum]++;
				pref[l - sum + vals[j] - (len - vals[j])]--;
			}
			sum -= vals[j];
			pos += vals[j];
		}
	}
	int cnt = 0, start = 0, ans = 0;
	for (auto i : pref) {
		bool no = cnt == 0;
		cnt += i.second;
		if (i.second > 0) {
			if (no) {
				start = i.first;
			}
		} else {
			if (cnt == 0) {
				ans += i.first - start;
				// cerr << start << ' ' << i.first - 1 << '\n';
			}
		}
	}
	cout << ans;
}

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 20 / 20
• Subtask 4: 21 / 21
• Subtask 5: 22 / 22
• Subtask 6: 13 / 13