Cod sursa(job #2001676)

Utilizator vladbatalanBatalan Vlad vladbatalan Data 17 iulie 2017 14:26:50
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.98 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("rmq.in");
ofstream fout("rmq.out");

int n, m, lg[100010], rmq[100010][20];

void precalculare()
{
    for(int i=2; i<=n; i++)
        lg[i] = lg[i/2]+1;
//    for(int i=1; i<=n; i++)
//        cout<<"lg["<<i<<"]="<<lg[i]<<'\n';
    for(int j=1; (1<<j)<=n; j++)
        for(int i=1; i<=n-(1<<j)+1; i++)
            rmq[i][j] = min(rmq[i][j-1], rmq[i+(1<<(j-1))][j-1]);
//    for(int j=0; (1<<j)<=n; j++){
//        for(int i=1; i<=n-(1<<j)+1; i++)
//            cout<<rmq[i][j]<<' ';
//        cout<<'\n';
//    }
}

int query(int x, int y)
{
    int j = lg[y-x+1];
//    cout<< "("<<x<<", "<<y<<"): "<<"j="<<j<<'\n';
    return min(rmq[x][j], rmq[y-(1<<j)+1][j]);
}

int main()
{
    int x, y;
    fin >> n >> m;
    for(int i=1; i<=n; i++)
        fin >> rmq[i][0];
    precalculare();
    for(int i=1; i<=m; i++)
    {
        fin >> x >> y;
        fout<<query(x, y)<<'\n';
    }
    return 0;
}