Cod sursa(job #2870078)

Utilizator toma_ariciuAriciu Toma toma_ariciu Data 12 martie 2022 07:34:46
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.57 kb
#include <iostream>
#include <fstream>

using namespace std;

const string filename = "arbint";
ifstream fin(filename + ".in");
ofstream fout(filename + ".out");

const int maxN = 100000;
int n, q, v[maxN], aint[4 * maxN];

void init_aint(int nod, int st, int dr)
{
    if(st == dr)
    {
        aint[nod] = v[st];
        return;
    }
    int med = (st + dr) / 2;
    init_aint(2 * nod, st, med);
    init_aint(2 * nod + 1, med + 1, dr);
    aint[nod] = max(aint[2 * nod], aint[2 * nod + 1]);
}

void update(int nod, int st, int dr, int poz, int val)
{
    if(st == dr)
    {
        aint[nod] = val;
        return;
    }
    int med = (st + dr) / 2;
    if(poz <= med)
        update(2 * nod, st, med, poz, val);
    if(med + 1 <= poz)
        update(2 * nod + 1, med + 1, dr, poz, val);
    aint[nod] = max(aint[2 * nod], aint[2 * nod + 1]);
}

int query(int nod, int st, int dr, int qst, int qdr)
{
    if(qst <= st && dr <= qdr)
        return aint[nod];
    int med = (st + dr) / 2, aux = -1;
    if(qst <= med)
        aux = max(aux, query(2 * nod, st, med, qst, qdr));
    if(med + 1 <= qdr)
        aux = max(aux, query(2 * nod + 1, med + 1, dr, qst, qdr));
    return aux;
}

int main()
{
    fin >> n >> q;
    for(int i = 1; i <= n; i++)
        fin >> v[i];
    init_aint(1, 1, n);
    for(int i = 1; i <= q; i++)
    {
        int cer, x, y;
        fin >> cer >> x >> y;
        if(cer == 1)
            update(1, 1, n, x, y);
        if(cer == 0)
            fout << query(1, 1, n, x, y) << '\n';
    }
    return 0;
}