Submission #1148503

#	Time	Username	Problem	Language	Result	Execution time	Memory
1148503		tianyaochiun	Trains (BOI24_trains)	C++20	100 / 100	517 ms	319820 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#define ll long long
#define pii pair<int,int> 
#define piii pair<pii,int>
#define F first
#define S second
#define pb push_back
#define eb emplace_back
#define endl "\n"
#define all(a) a.begin(),a.end()
#define int long long
 
const int mod=1e9+7,C=400;
 
void solve(){
	int n,ans=0;
	cin>>n;
	vector<int> d(n),x(n),dp(n);
	vector<vector<int>> add(n,vector<int>(C+1));
	dp[0]=1;
	for(int i=0;i<n;i++){
		cin>>d[i]>>x[i];
		for(int j=1;j<=C;j++){
			(dp[i]+=add[i][j])%=mod;
			if(i+j<n) (add[i+j][j]+=add[i][j])%=mod;
		}
		(ans+=dp[i])%=mod;
		if(i+d[i]>=n||x[i]==0||d[i]==0) continue;
		if(d[i]<=C){
			(add[i+d[i]][d[i]]+=dp[i])%=mod;
			if(i+d[i]*(x[i]+1)<n) (add[i+d[i]*(x[i]+1)][d[i]]+=mod-dp[i])%=mod;
		}
		else{
			for(int j=i+d[i];j<=min(n-1,i+d[i]*x[i]);j+=d[i]) (dp[j]+=dp[i])%=mod;
		}
	}
	cout<<ans;
}
 
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t=1;
	//cin>>t;
	while(t--){
		solve();
	}
	return 0;
}

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