Cod sursa(job #2573150)

Utilizator halexandru11Hritcan Alexandru halexandru11 Data 5 martie 2020 16:02:12
Problema Range minimum query Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.57 kb
#include <bits/stdc++.h>

using namespace std;

#define nax 100005

ifstream f("rmq.in");
ofstream g("rmq.out");

vector<int> a;
vector<int> lg, arb[nax];
int n, m;

void Read()
{
    int i;
    f >> n >> m;
    a.resize(n);
    lg.resize(n);
    for(i = 0; i < n; ++i)
    {
        f >> a[i];
    }
}

void Processing()
{
    int i, j;

    // lg[i] = log2(i)
    for(i = 1; (1 << i) <= n; ++i)
        for(j = (1 << i) - 1; j < (1 << (i+1)) && j < n; ++j)
            lg[j] = i;

    // setez dimensiunea fiecarei linii din arb
    for(i = 0; i < n; ++i)
    {
        arb[i].resize(lg[n - i - 1] + 1);
        arb[i][0] = i;
    }

    // completez arb
    for(j = 1; (1 << j) < n; ++j)
    {
        for(i = 0; i + (1 << j) - 1 < n; ++i)
        {
            if(a[arb[i][j-1]] <= a[arb[i + (1 << (j-1))][j-1]])
                arb[i][j] = arb[i][j-1];
            else
                arb[i][j] = arb[i + (1 << (j-1))][j-1];
        }
    }
}

int Rmq(int& st, int& dr)
{
    if(st > dr)
    {
        st ^= dr;
        dr ^= st;
        st ^= dr;
    }

    int power = lg[dr - st + 1] - 1;
    return min(a[arb[st][power]], a[arb[dr + 1 - (1 << power)][power]]);
}

int main()
{
    Read();
    Processing();

    int i, st, dr;
    for(i = 0; i < m; ++i)
    {
        f >> st >> dr;
        --st; --dr;
        g << Rmq(st, dr) << "\n";
    }

    for(int i = 0; i < n; ++i)
    {
        for(int j = 0; j <= lg[n-i-1]; ++j)
            cout << arb[i][j] << " ";
        cout << "\n";
    }
    return 0;
}