Submission #733005

#	Time	Username	Problem	Language	Result	Execution time	Memory
733005		SanguineChameleon	Boat (APIO16_boat)	C++17	9 / 100	130 ms	468 KiB

boat

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

void just_do_it();

int main() {
	#ifdef KAMIRULEZ
		freopen("kamirulez.inp", "r", stdin);
		freopen("kamirulez.out", "w", stdout);
	#endif
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	just_do_it();
	return 0;
}

const int maxn = 5e2 + 20;
const long long mod = 1e9 + 7;
bool flag[maxn];
long long cur[maxn];
long long nxt[maxn];
pair<int, int> events[maxn * 2];
int n;

void trans() {
	for (int i = 1; i <= n; i++) {
		nxt[i] = cur[i];
		if (flag[i]) {
			nxt[i] = (nxt[i] + 1) % mod;
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = i + 1; j <= n; j++) {
			if (flag[j]) {
				nxt[j] = (nxt[j] + cur[i]) % mod;
			}
		}
	}
	swap(cur, nxt);
}

void just_do_it() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		int a, b;
		cin >> a >> b;
		events[i * 2 - 1] = make_pair(a, i);
		events[i * 2] = make_pair(b + 1, -i);
	}
	sort(events + 1, events + n * 2 + 1);
	int cur_t = 0;
	for (int i = 1; i <= n * 2; i++) {
		int nxt_t = events[i].first;
		int id = events[i].second;
		bool begin_t = (i == 1 || events[i].first != events[i - 1].first);
		bool end_t = (i == n * 2 || events[i].first != events[i + 1].first);
		if (begin_t) {
			if (cur_t < nxt_t - 1) {
				for (int i = 1; i <= n; i++) {
					assert(!flag[i]);
				}
				cur_t = nxt_t - 1;
			}
		}
		if (id > 0) {
			flag[id] = true;
		}
		else {
			flag[-id] = false;
		}
		if (end_t && cur_t == nxt_t - 1) {
			trans();
			cur_t = nxt_t;
		}
	}
	long long res = 0;
	for (int i = 1; i <= n; i++) {
		res += cur[i];
		res %= mod;
	}
	cout << res;
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42