Cod sursa(job #2144167)

Utilizator LittleWhoFeraru Mihail LittleWho Data 26 februarie 2018 16:18:14
Problema Stramosi Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.79 kb
#include <bits/stdc++.h>

using namespace std;

int n, m;
int dp[20][250001];
int lg2[250001];

int query(int x, int k ) {
    if (k == 0 || x == 0) return x;

    return query(dp[lg2[k]][x], k - (1 << lg2[k]));
}

int main() {
    freopen("carici.in", "r", stdin);

    freopen("stramosi.in", "r", stdin);
    freopen("srtamosi.out", "w", stdout);

    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i++) {
        scanf("%d", &dp[0][i]);
    }

    lg2[0] = 1;
    for (int i = 2; i <= n; i++) {
        lg2[i] = lg2[i / 2] + 1;
    }

    for (int i = 1; i <= lg2[n]; i++) {
        for (int j = 1; j <= n; j++) {
            dp[i][j] = dp[i - 1][dp[i - 1][j]];
        }
    }

    int x, y;
    while (m--) {
        scanf("%d%d", &x, &y);
        cout << query(x, y) << "\n";
    }

    return 0;
}