Submission #1111610

#	Time	Username	Problem	Language	Result	Execution time	Memory
1111610		gohchingjayk	Trains (BOI24_trains)	C++17	0 / 100	2 ms	1616 KiB

Main

#include <bits/stdc++.h>

using namespace std;
using i64 = int64_t;

int mod = 1'000'000'007;
vector<int> parents[10000];
bool dp[10000];

int search(int i) {
	int ans = 0;
	if (i == 0) return 1;
	if (dp[i]) return 0;
	for (int parent : parents[i]) {
		ans = (ans + search(parent)) % mod;
	}
	dp[i] = true;
	return ans;
}

int main() {
	cin.tie(0);
	cout.tie(0);
	ios_base::sync_with_stdio(false);

	int N; cin >> N;

	for (int i = 0; i < N; ++i) {
		int d, x;
		cin >> d >> x;
		if (d == 0) continue;

		for (int j = i + d; j < N && j <= i + d * x; ++j) {
			parents[j].emplace_back(i);
		}
	}

	int sum = 1;
	for (int i = 1; i < N; ++i)
	{
		memset(dp, 0, sizeof(dp));
		sum = (sum + search(i)) % mod;
	}
	cout << sum;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 13
• Subtask 3: 0 / 16
• Subtask 4: 0 / 34
• Subtask 5: 0 / 29