Submission #1105129

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105129		alexdd	Trains (BOI24_trains)	C++17	100 / 100	745 ms	990208 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9+7;
const int LIM = 400;
int n;
vector<int> tole[100005];
int dp[100005];
vector<int> events[100005][LIM+5];
int s[LIM+5][LIM+5];
signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n;
    int d,x;
    for(int i=1;i<=n;i++)
    {
        cin>>d>>x;
        if(d==0 || x==0 || i+d>n)
            continue;
        if(d<=LIM)
        {
            int ri = i + min((n-i)/d,x)*d;
            events[i+d][d].push_back(i);
            if(ri+d<=n) events[ri+d][d].push_back(-i);
        }
        else
        {
            for(int j=1;j<=x;j++)
            {
                if(i+j*d>n)
                    break;
                tole[i+j*d].push_back(i);
            }
        }
    }
    dp[1]=1;
    int rez=1;
    for(int i=2;i<=n;i++)
    {
        for(int j=1;j<=LIM;j++)
        {
            for(int e:events[i][j])
            {
                if(e>0)
                {
                    s[j][i%j] = (s[j][i%j] + dp[e])%MOD;
                }
                else
                {
                    e = -e;
                    s[j][i%j] = (s[j][i%j] + MOD - dp[e])%MOD;
                }
            }
            dp[i] = (dp[i] + s[j][i%j])%MOD;
        }
        for(int j:tole[i])
        {
            dp[i] = (dp[i] + dp[j])%MOD;
        }
        rez = (rez + dp[i])%MOD;
    }
    cout<<rez;
    return 0;
}

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