Cod sursa(job #640732)

Utilizator mlupseLupse-Turpan Mircea mlupse Data 26 noiembrie 2011 13:46:28
Problema Stramosi Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.72 kb
using namespace std;
#include <fstream>
#define NMax 250005
#define LgMax 19

ifstream fin ("stramosi.in");
ofstream fout ("stramosi.out");

int N,M,A[LgMax][NMax],L[NMax];

void BuildLog2 ()
{
    for (int i=2; i<=250000; ++i)
        L[i]=L[i>>1]+1;
}

void Build()
{
    BuildLog2 ();
    for (int i=1; i<=L[N]; ++i)
        for (int j=1; j<=N; ++j)
            A[i][j]=A[i-1][A[i-1][j]];
}

int Find(int X, int K)
{
    while (K*X>0)
    {
        X=A[L[K]][X];
        K-=(1<<L[K]);
    }
    return X;
}

int main()
{
	int X, Y;
    fin >> N >> M;
    for (int i=1; i<=N; ++i)
        fin >> A[0][i];
  
    Build();
    for (; M>0; --M)
    {
        fin >> X >> Y;
        fout << Find(X, Y) << "\n";
    }
    return 0;
}