제출 #1237337

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1237337		zadniprovska	Trains (BOI24_trains)	C++20	21 / 100	67 ms	836 KiB

Main

#include <bits/stdc++.h>

using namespace std;


#define ll long long

const ll DIM = 1e5 + 7;
const ll mod = 1e9 + 7;

ll dp[DIM], diff[DIM];

int main(){
    ios::sync_with_stdio(false);cin.tie(nullptr); cout.tie(nullptr);
    

    ll n;
    cin >> n;

    if (n <= 10000) {

        dp[1] = 1;
        for (int i=1; i<=n; i++) {
            ll d, x;
            cin >> d >> x;

            if (d == 0) continue;

            for (int j=i+d; j<=min(n, i + x*d); j+=d) {
                dp[j] += dp[i];
                dp[j] %= mod;
            }
        }

        ll answer = 0;
        for (int i=1; i<=n; i++) {
            answer += dp[i];
            answer %= mod;
        }
        cout << answer << endl;
    }

    else {
        diff[2] = -1;
        ll dp = 1, answer = 0;
        for (int i=1; i<=n; i++) {
            ll d, x;
            cin >> d >> x;

            // i+d ... i + x*d

            diff[i+d]+=dp;
            diff[i+d] %= mod;
            diff[min(n, i+x*d) + 1]-=dp;
            diff[min(n, i+x*d) + 1] %= mod;

            answer += dp;
            answer %= mod;

            dp = dp + diff[i+1];
            dp %= mod;
        }

        cout << answer << endl;
    }

}
;

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