Cod sursa(job #1690513)

Utilizator BugirosRobert Bugiros Data 15 aprilie 2016 11:06:21
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.41 kb
#include <fstream>
using namespace std;

ifstream in("arbint.in");
ofstream out("arbint.out");

const int MAXN = 100005;

int arbore[4 * MAXN];
int n;

void actualizare(int nod, int st, int dr, int poz, int val)
{
    if (st == dr)
    {
        arbore[nod] = val;
        return;
    }
    int mij = (st + dr) / 2;
    if (poz <= mij)
        actualizare(2 * nod, st, mij, poz, val);
    else actualizare(2 * nod + 1, mij + 1, dr, poz, val);
    arbore[nod] = max(arbore[2 * nod], arbore[2 * nod + 1]);
}

int interogare(int nod, int st, int dr, int sti, int dri)
{
    if (st == sti && dr == dri)
        return arbore[nod];
    int mij = (st + dr) / 2;
    if (dri <= mij)
        return interogare(2 * nod, st, mij, sti, dri);
    if (sti > mij)// >= mij + 1
        return interogare(2 * nod + 1, mij + 1,dr, sti, dri);
    return max(interogare(2 * nod, st, mij, sti, mij),
               interogare(2 * nod + 1, mij + 1, dr, mij + 1, dri));
}



void citire(int &m)
{
    in >> n >> m;
    for (int i = 1;i <= n;++i)
    {
        int x;
        in >> x;
        actualizare(1, 1, n, i, x);
    }
}

int main()
{
    int m;
    citire(m);
    while (m > 0)
    {
        int t,a,b;
        in >> t >> a >> b;
        if (t == 0)//interogare
            out << interogare(1, 1, n, a, b) << '\n';
        else actualizare(1, 1, n, a, b);
        --m;
    }
    return 0;
}