Submission #1002129

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002129		Khanhcsp2	Trains (BOI24_trains)	C++14	71 / 100	239 ms	396884 KiB

Main

#include<bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=1e5+11;
int n, d[N], x[N], dp[N], pfs[N][501];
void sol()
{
    cin >> n;
    for(int i=1; i<=n; i++) cin >> d[i] >> x[i];
    for(int i=n; i>=1; i--)
    {
        dp[i]=1;
        if(d[i]>=500) for(int j=1; j<=x[i] && i+j*d[i]<=n; j++) dp[i]=(dp[i]+dp[i+j*d[i]])%mod;
        else if(d[i])
        {
            if(i+d[i]<=n) dp[i]=(dp[i]+pfs[i+d[i]][d[i]])%mod;
            if(i+d[i]*(x[i]+1ll)<=n) dp[i]=(dp[i]-pfs[i+d[i]*(x[i]+1ll)][d[i]])%mod;
        }
        for(int j=1;j<500;j++)
        {
            pfs[i][j]=dp[i];
            pfs[i][j]=(pfs[i][j]+pfs[i+j][j])%mod;
        }
    }
    cout << (dp[1]+mod)%mod;
}
signed main()
{
//    freopen("divisor.INP", "r", stdin);
//    freopen("divisor.OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin >> t;
    while(t--)
    {
        sol();
    }
}

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