Submission #1052949

#	Time	Username	Problem	Language	Result	Execution time	Memory
1052949		vjudge1	Trains (BOI24_trains)	C++17	100 / 100	235 ms	8020 KiB

Main

#include <iostream>
#include <vector>

using namespace std;
#define int long long
const int N = 1e5 + 5;
int dp[N], mod = 1e9 + 7, Ans;
int Mod[505][505];
vector<pair<int,int>> rem[N];

signed main(){
	int n;
	cin>>n;
	dp[1] = 1;
	for (int i=1, d, x;i<=n;i++){
		cin>>d>>x;
		for (int m=1;m<=500;m++)
			dp[i] = (dp[i] + Mod[m][i % m]) % mod;

		if (d > 500){
			for (int j=d;j/d<=x and i + j <= n;j+=d)
				dp[j + i] = (dp[j + i] + dp[i]) % mod;
		}
		else if (d){
			Mod[d][i % d] = (Mod[d][i % d] + dp[i]) % mod;
		}

		if (d and d <= 500 and d * x + i <= n)
			rem[d * x + i].push_back({i, d});
		
		for (auto [ind, d_ind] : rem[i])
			Mod[d_ind][ind % d_ind] = (Mod[d_ind][ind % d_ind] - dp[ind] + mod) % mod;
		Ans = (Ans + dp[i]) % mod;
		// exit by removing those 
	}
	cout<<Ans<<'\n';
}

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