Cod sursa(job #2485360)

Utilizator Dragos1226Dragos Chileban Dragos1226 Data 1 noiembrie 2019 13:37:59
Problema Stramosi Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.82 kb
#include<fstream>
#include<vector>
#include<cmath>
using namespace std;
ifstream in("stramosi.in");
ofstream out("stramosi.out");

const int NMax = 250000;
vector <int> G[NMax+5];

int N, T, A[20][NMax+5], lg[NMax+5];

void Read() {
    in >> N >> T;
    for (int i = 1; i <= N; i++) {
        in >> A[0][i];
    }

    for (int i = 1; (1<<i) <= N; i++)
            for (int j = 1; j <= N; j++)
        A[i][j] = A[i-1][A[i-1][j]];

}

int Ancestor(int Q, int P) {
    while (P > 0) {
        int K = lg[P];
        P -= 1<<K;
        Q=A[K][Q];
    }

    return Q;
}

void Solve() {
    for (int i = 2; i <= N; i++)
        lg[i] = lg[i/2] + 1;
    while(T--) {
        int P, Q;
        in >> Q >> P;
        out << Ancestor(Q, P) << '\n';
    }
}

int main() {
    Read();
    Solve();
}