Submission #1309673

#	Time	Username	Problem	Language	Result	Execution time	Memory
1309673		meesha284	Trains (BOI24_trains)	C++17	50 / 100	132 ms	6768 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define vp vector<pair<ll, ll>>
#define vpp vector<pair<ll, pair<ll, ll>>>
#define pp pair<ll, ll>
#define qi queue<ll>
#define qp queue<pp>
#define pqi priority_queue<ll>
#define pqp priority_queue<pp>
#define mi map<ll, ll>
#define mpi map<pp, ll>
#define mip map<ll, pp>
#define mp map<pp, pp>
#define mb map<ll, bool>
#define si set<ll>
#define sp set<pp>
#define sc set<char>
#define mod 1000000007
#define inf 1000000000000000000
#define all(x) (x).begin(), (x).end()
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll n;
    cin >> n;
    vi d(n + 1), x(n + 1);
    for(int i = 1; i <= n; i++) cin >> d[i] >> x[i];
    ll LIM = sqrt(n);
    vi dp(n + 1, 0);
    dp[1] = 1;
    vvi add(LIM);
    for(int i = 1; i < LIM; i++) {
        add[i] = vi(i, 0);
    }

    vector<vector<pair<pp, ll>>> ends(n + 1);
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j < LIM; j++) {
            ll rem = i % j;
            dp[i] = (dp[i] + add[j][rem]) % mod;
        }
        for(auto[t, val] : ends[i]) {
            auto[div, rem] = t;
            add[div][rem] = (mod + add[div][rem] - val) % mod;
        }

        if(d[i] == 0) continue;
        if(d[i] >= LIM) {
            for(int j = 1; j <= x[i]; j++) {
                ll stop = i + d[i] * j;
                if(stop > n) break;
                dp[stop] += dp[i];
                dp[stop] %= mod;
            }
        }
        else {
            ll rem = i % d[i];
            add[d[i]][rem] = (add[d[i]][rem] + dp[i]) % mod;
            
            ll last = i + d[i] * x[i];
            if(last > n) continue;
            ends[last].push_back({{d[i], rem}, dp[i]});
        }
    }
    ll ans = 0;
    for(int i = 1; i <= n; i++) ans = (ans + dp[i]) % mod;
    cout << ans << '\n';
    return 0;
}

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