Submission #995473

#	Time	Username	Problem	Language	Result	Execution time	Memory
995473		12345678	Trains (BOI24_trains)	C++17	0 / 100	107 ms	5980 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5, mod=1e9+7, kx=255;

int n, d[nx], x[nx], qs[kx][kx], dp[nx], res, sm=1, k=250;
vector<int> rem[nx];

void add(int idx)
{
    if (d[idx]==0) return;
    if (d[idx]>k)
    {
        for (int i=idx+d[i], j=0; j<x[idx]&&i<=n; j++, i+=d[i]) dp[i]=(dp[i]+dp[idx])%mod;
    }
    else
    {
        qs[d[idx]][idx%d[idx]]=(qs[d[idx]][idx%d[idx]]+dp[idx])%mod;
        if (idx+x[idx]*d[idx]<=n) rem[idx+x[idx]*d[idx]].push_back(idx); 
    }
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=1; i<=n; i++) cin>>d[i]>>x[i];
    dp[1]=1;
    add(1);
    for (int i=2; i<=n; i++)
    {
        for (int j=1; j<=k; j++) dp[i]=(dp[i]+qs[j][i%j])%mod;
        add(i);
        for (auto idx:rem[i]) qs[d[idx]][idx%d[idx]]=(((qs[d[idx]][idx%d[idx]]-dp[idx])%mod)+mod)%mod;
    }
    for (int i=1; i<=n; i++) res=(res+dp[i])%mod;
    cout<<res;
}

Compilation message (stderr)

Main.cpp: In function 'void add(int)':
Main.cpp:15:27: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
   15 |         for (int i=idx+d[i], j=0; j<x[idx]&&i<=n; j++, i+=d[i]) dp[i]=(dp[i]+dp[idx])%mod;
      |                        ~~~^

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