Submission #994579

#	Time	Username	Problem	Language	Result	Execution time	Memory
994579		kym	Trains (BOI24_trains)	C++14	50 / 100	176 ms	10976 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long 
#ifdef LOCAL
void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif
const int MAXN = 100005;
const int inf=1000000500ll;
const long long oo =1000000000000000500ll;
const int MOD = (int)1e9+7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef pair<int,int> pi; 
const int sqn=400;
int n;
int D[MAXN], X[MAXN];
int dp[MAXN];
int R[sqn+5][sqn+5];
vector<array<int,3>> C[MAXN]; // at C_i, we need to remove x.first from x.second

int32_t main() 
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> n;
	dp[1]=1;
	for(int i=1;i<=n;i++){
		cin>>D[i]>>X[i];
	}
	int ans=0;
	for(int i=1;i<=n;i++){
		for(int r=1;r<=sqn;r++){
			dp[i]=(dp[i] + R[r][i%r])%MOD;
		}
		if(D[i] > sqn){
			for(int t=1;t<=X[i];t++){
				int idx=i+t*D[i];
				if(idx<=n){
					dp[idx] = (dp[idx] + dp[i])%MOD;
				} else{
					break;
				}
			}
		} else{
			R[D[i]][i%D[i]]=(R[D[i]][i%D[i]]+dp[i])%MOD;
			int idx=min(n+1,i+X[i]*D[i]);
			C[idx].push_back({D[i],i%D[i],dp[i]});
		}
		for(auto x:C[i]){
			R[x[0]][x[1]]=(R[x[0]][x[1]]-x[2]+MOD)%MOD;
		}
		ans=(ans+dp[i])%MOD;
	}
	cout<<ans;
}

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