Cod sursa(job #1376962)

Utilizator lacraruraduRadu Matei Lacraru lacraruradu Data 5 martie 2015 19:31:06
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>

#define maxim(x, y) x > y ? x : y
using namespace std;

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

int n, m;
int arbint[(1 << 18)];

void actualizare(int nod, int st, int dr, int a, int b, int val)
{
    if(a <= st && dr <= b)
    {
        arbint[nod] = val;
        return;
    }

    int mij = (st + dr) >> 1;
    if(a <= mij)
        actualizare(nod << 1, st, mij, a, b, val);
    if(mij + 1 <= b)
        actualizare((nod << 1) + 1, mij + 1, dr, a, b, val);
    arbint[nod] = maxim(arbint[nod << 1], arbint[(nod << 1) + 1]);
}

int interogare(int nod, int st, int dr, int a, int b)
{
    if(a <= st && dr <= b)
        return arbint[nod];

    int mij = (st + dr) >> 1;
    int rez = 0;
    if(a <= mij)
        rez = maxim(rez, interogare(nod << 1, st, mij, a, b));
    if(mij + 1 <= b)
        rez = maxim(rez, interogare((nod << 1) + 1, mij + 1, dr, a, b));
    return rez;
}

int main()
{
    in >> n >> m;

    for(int i = 1; i <= n; i++)
    {
        int val;
        in >> val;
        actualizare(1, 1, n, i, i, val);
    }

    for(int i = 1; i <= m; i++)
    {
        int op, a, b;
        in >> op >> a >> b;

        if(op == 0)
            out << interogare(1, 1, n, a, b) << '\n';
        else
            actualizare(1, 1, n, a, a, b);
    }
    return 0;
}