Submission #1123225

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123225		Pwo	Trains (BOI24_trains)	C++17	21 / 100	2093 ms	1828 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int m = 1e9 + 7;

int n, dp[100005];
pair<int, int> a[100005];

int32_t main() {
	ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> a[i].first >> a[i].second;
	dp[1] = 1;
	for (int i = 2; i <= n; i++) {
		for (int j = 1; j < i; j++) {
			if (a[j].first == 0) continue;
			int d = i - j;
			if (d % a[j].first == 0
				&& (d / a[j].first) <= a[j].second)
				dp[i] = (dp[i] + dp[j]) % m;
		}
	}
	
	int ans = 0;
	for (int i = 1; i <= n; i++) ans = (ans + dp[i]) % m;
	cout << ans;
}

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