Submission #1033697

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033697		hehebjp123	Trains (BOI24_trains)	C++14	100 / 100	268 ms	254868 KiB

Main

#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define pb push_back
using namespace std;
const ll N=1e5+9;
const ll mod=1e9+7;
const ll S=320;
ll f[S+2][N],dp[N],i,j,n,x[N],d[N];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cin>>n;
    for(i=1;i<=n;i++) cin>>d[i]>>x[i];
    memset(dp,0,sizeof(dp));
    memset(f,0,sizeof(f));
    for(i=n;i>0;i--)
    {
        if(d[i]>=S)
        {
            for(j=i+d[i];j<=n;j+=d[i])
                if((j-i)/d[i]<=x[i])
                dp[i]+=dp[j];
        }
        else {
            dp[i]+=f[d[i]][i];
    if(i+(x[i]+1)*d[i]<=n) dp[i]-=f[d[i]][i+(x[i]+1)*d[i]];
        }
        dp[i]=(dp[i]+mod+1)%mod;
        for(j=1;j<=S;j++)
        {
            f[j][i]=(f[j][i]+dp[i])%mod;
            if(i>j)
            f[j][i-j]=(f[j][i-j]+f[j][i])%mod;
        }
    }
    cout<<dp[1];
}
/*
5
1 3
2 1
1 3
0 10
3 5

*/

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