Cod sursa(job #3367789)

Utilizator horia_Horia Casuneanu horia_ Data 10 octombrie 2026 17:07:22
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
#include <bits/stdc++.h>

using namespace std;

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

int n, m;
int v[100005], arb[400005];

void build(int nod, int st, int dr)
{
    if (st == dr) {arb[nod] =  v[st]; return;}
    int mij = (st + dr) / 2;
    build(2 * nod, st, mij);
    build(2 * nod + 1, mij + 1, dr);
    arb[nod] = max(arb[2 * nod], arb[2 * nod + 1]);
}

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

int query(int nod, int st, int dr, int l, int r)
{
    int maxim = 0;
    if (l <= st && r >= dr) {return arb[nod];}
    int mij = (st + dr) / 2;
    if (mij >= l)
        maxim = max(maxim, query(2 * nod, st, mij, l, r));
    if (mij + 1 <= r)
        maxim = max(maxim, query(2 * nod + 1, mij + 1, dr, l , r));
    return maxim;
}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= n; ++i) fin >> v[i];
    build(1, 1, n);
    for (int i = 1; i <= m; ++i)
    {
        int tip, st, dr;
        fin >> tip >> st >> dr;
        if (tip == 0)
            fout << query(1, 1, n, st, dr) << '\n';
        else
            update(1, 1, n, st, dr);
    }
    return 0;
}