Cod sursa(job #2070581)

Utilizator abccnuCamelia Zalum abccnu Data 19 noiembrie 2017 18:21:32
Problema Stramosi Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.01 kb
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

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

const int NMAX = 250005;
int v[NMAX], N, Q;
int rmq[NMAX][20], lg[NMAX];

void pr()
{
    lg[2] = 1;
    for (int i = 3; i < NMAX; i++) lg[i] = lg[i >> 1] + 1;
    for (int j = 1; j <= 17; ++j)
    {
        for (int i = 1; i <= N; ++i)
        {
            int stramos_jminusunu = rmq[i][j - 1];
            rmq[i][j] =  rmq[stramos_jminusunu][j - 1];// f(f(j - 1))
        }
    }
}

int RMQ (int x, int y)
{
    for (int i = lg[y]
         ; i >= 0; i--)
        if (y & (1 << i))
            x = rmq[x][i];
    return x;
}


void read()
{
    fin >> N >> Q;

    for (int i = 1; i<=N; ++i)
    {
        fin >> v[i];
        rmq[i][0] = v[i];
    }

    pr();

    int x, y;

    for (int i = 1; i<=Q; ++i)
    {
        fin >> x >> y;
        fout << RMQ(x, y)<< "\n";
    }

}


int main()
{

read();
    return 0;
}