Cod sursa(job #3242587)

Utilizator Sasha_12454Eric Paturan Sasha_12454 Data 12 septembrie 2024 18:40:08
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.81 kb
#include <bits/stdc++.h>

const std :: string FILENAME = "arbint";

std :: ifstream in (FILENAME + ".in");

std :: ofstream out (FILENAME + ".out");

const int NMAX = 1e5 + 5;

int n;

int q;

int cer;

int x;

int y;

int v[NMAX];

int arb[4 * NMAX];

void gen(int nod, int st, int dr)
{
    if(st == dr)
    {
        arb[nod] = v[st];
    }
    else
    {
        int mij = (st + dr) / 2;

        gen(2 * nod, st, mij);

        gen(2 * nod + 1, mij + 1, dr);

        arb[nod] = std :: max(arb[nod * 2], arb[nod * 2 + 1]);
    }
}

int query(int nod, int st, int dr, int q_st, int q_dr)
{
    if(q_st <= st && q_dr >= dr)
    {
        return arb[nod];
    }

    int mij = (st + dr) / 2;

    if(q_dr <= mij)
    {
        return query(nod * 2, st, mij, q_st, q_dr);
    }

    if(q_st > mij)
    {
        return query(nod * 2 + 1, mij + 1, dr, q_st, q_dr);
    }

    return std :: max(query(nod * 2, st, mij, q_st, q_dr), query(nod * 2 + 1, mij + 1, dr, q_st, q_dr));
}

void update(int nod, int st, int dr, int poz, int val)
{
    if(st == dr)
    {
        arb[nod] = val;
    }
    else
    {
        int mij = (st + dr) / 2;

        if(poz <= mij)
        {
            update(nod * 2, st, mij, poz, val);
        }
        else
        {
            update(nod * 2 + 1, mij + 1, dr, poz, val);
        }

        arb[nod] = std :: max(arb[nod * 2], arb[nod * 2 + 1]);
    }
}

int main()
{

    in >> n >> q;

    for(int i = 1; i <= n; i ++)
    {
        in >> v[i];
    }

    gen(1, 1, n);

    while(q --)
    {
        in >> cer >> x >> y;

        if(cer == 0)
        {
            out << query(1, 1, n, x, y) << '\n';
        }
        else
        {
            update(1, 1, n, x, y);
        }
    }

    return 0;
}