제출 #1290509

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1290509		Art	Trains (BOI24_trains)	C++20	100 / 100	129 ms	129624 KiB

Main

//      - Art -
#include <bits/stdc++.h>

#define el              cout << '\n'

#define FOR(i, a, b)    for (int i = (a), _b = (b); i <= _b; ++i)
#define REV(i, b, a)    for (int i = (b), _a = (a); i >= _a; --i)
#define REP(i, c)       for (int i = 0, _c = (c); i < _c; ++i)

const int N = 2e5 + 7;
const int BLOCKSIZE = 320;
const int MOD = 1e9 + 7;

using namespace std;

int x[N], d[N];
int dp[N], f[N][BLOCKSIZE + 7];

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    int n;
    cin >> n;
    FOR (i, 1, n) {
        cin >> d[i] >> x[i];
        dp[i] = 1;
    }

    REV (i, n, 1) {
        if (d[i] > BLOCKSIZE) {
            for (int j = i + d[i]; j <= min(1LL * n, i + 1LL * x[i] * d[i]); j += d[i]) {
                dp[i] = (dp[i] + dp[j]) % MOD;
            }
        }
        else {
            if (i + d[i] <= n) {
                dp[i] = (1LL * dp[i] + f[i + d[i]][d[i]] - f[min(i + 1LL * (x[i] + 1) * d[i], 1LL * n + 1)][d[i]] + MOD) % MOD;
            }
        }
        FOR (j, 1, BLOCKSIZE) {
            int add = 0;
            if (i + j <= n) {
                add = f[i + j][j];
            }
            f[i][j] = (dp[i] + add) % MOD;
        }
    }
    cout << dp[1], el;

    return 0;
}

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