Cod sursa(job #3204947)

Utilizator v_mateiVatamanu Matei v_matei Data 18 februarie 2024 13:25:59
Problema Stramosi Scor 70
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.84 kb
#include <fstream>
#include <iostream>
#include <vector>

#define NMAX 250'007

std::ifstream cin("stramosi.in");
std::ofstream cout("stramosi.out");

int n, m;
int stramos[NMAX], vis[NMAX], dp[NMAX][40];

void citire() {
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    cin >> stramos[i];
  }
}

int ancestor(int x, int k) {
  if (k == 0)
    return x;
  if(stramos[x] == 0)
    return 0;
  return ancestor(stramos[x], k - 1);
}

void queries() {
  int q, p;
  for (int i = 1; i <= m; i++) {
    cin >> q >> p;
    int anc = q;
    int d = 0;
    while (p >> d) {
      if ((p >> d) % 2) {
        anc = dp[anc][d];
      }
      d++;
    }
    cout << anc << '\n';
  }
}

int main() {
  citire();

  for (int i = 0; (1 << i) <= n; i++) {
    for (int j = 1; j <= n; j++) {
      dp[j][i] = ancestor(j, (1 << i));
    }
  }
  queries();
  return 0;
};