Submission #1111429

#	Time	Username	Problem	Language	Result	Execution time	Memory
1111429		gelastropod	Trains (BOI24_trains)	C++14	21 / 100	2100 ms	10064 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define int long long

vector<pair<int, int>> vals;
vector<int> dp;

int ways(int n)
{
    if (dp[n] != -1) return dp[n];
    if (vals[n].first == 0 || n + vals[n].first >= (int)dp.size()) return dp[n] = 1;
    int ans = 1;
    for (int i = n + vals[n].first, t = 0; i < (int)dp.size() && t < vals[n].second; i += vals[n].first, t++)
    {
        ans += ways(i);
        ans %= 1000000007;
    }
    return dp[n] = ans;
}

signed main()
{
    int N, a, b;
    cin >> N;
    dp = vector<int>(N, -1);
    for (int i = 0; i < N; i++)
    {
        cin >> a >> b;
        vals.push_back({a, b});
    }
    cout << ways(0) << '\n';
}

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