Cod sursa(job #2192814)

Utilizator AndreiDumitrescuAndrei Dumitrescu AndreiDumitrescu Data 7 aprilie 2018 13:20:15
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.48 kb
#include <iostream>
#include <fstream>
#define maxN 400005
#define inf -9999999
using namespace std;

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

int arbint[maxN], v[100005], n, m;


int maxim(int a, int b)
{
    if(a > b)
        return a;
    else
        return b;
}

int actualizare(int nod, int st, int dr, int poz)
{
    if(st == dr)
        arbint[nod] = v[poz];
    else
    {
        int mij =(st + dr) / 2;
        if(poz > mij)
            actualizare(2 * nod + 1, mij+1, dr, poz);
        else
            actualizare(2*nod, st, mij, poz);
        arbint[nod] = maxim(arbint[2*nod + 1], arbint[2*nod]);
    }
}
int interogare(int nod, int st, int dr, int a, int b)
{
    if(a <= st && b >= dr)
    {
       return arbint[nod];
    }
    else
    {
        int mij =(st + dr) / 2, MaxLeft = inf, MaxRight = inf;
        if(a <= mij)
            MaxLeft = interogare(2 * nod , st, mij, a, b);
        if(b > mij)
            MaxRight = interogare(2*nod + 1, mij+1, dr, a, b);
        return maxim(MaxRight, MaxLeft);
    }

}
int main()
{
    f >> n >> m;
    int i, a, b, c;
    for(i = 1; i <= n ; i++)
    {
        f >> v[i];
        actualizare(1, 1, n , i);
    }
    for(i = 1; i <= m; i++)
    {
        f >> c >> a >> b;
        if(c == 1)
        {
            v[a] = b;
            actualizare(1, 1, n, a);
        }
        else
        {
            g << interogare(1, 1, n, a, b) << '\n';
        }
    }
}