Cod sursa(job #2724900)

Utilizator niculaandreiNicula Andrei Bogdan niculaandrei Data 18 martie 2021 01:03:24
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.3 kb
#include <bits/stdc++.h>

using namespace std;

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

const int N_MAX = 1e5 + 5;

int N, M, x;
int aint[4 * N_MAX];

void Update(int node, int l, int r, int pos, int val)
{
    if (l == r)
    {
        aint[node] = val;
        return;
    }

    int mid = (l + r) / 2;
    if (pos <= mid)
        Update(2 * node, l, mid, pos, val);
    else
        Update(2 * node + 1, mid + 1, r, pos, val);
    aint[node] = max(aint[2 * node], aint[2 * node + 1]);
}

int Query(int node, int lo, int hi, int l, int r)
{
    if (lo == l && hi == r)
        return aint[node];

    int mid = (lo + hi) / 2;
    if (r <= mid)
        return Query(2 * node, lo, mid, l, r);
    else if (l > mid)
        return Query(2 * node + 1, mid + 1, hi, l, r);
    else
        return max(Query(2 * node, lo, mid, l, mid), Query(2 * node + 1, mid + 1, hi, mid + 1, r));
}

int main()
{
    fin >> N >> M;
    for (int i = 1; i <= N; i++)
    {
        fin >> x;
        Update(1, 1, N, i, x);
    }
    for (int i = 1; i <= M; i++)
    {
        int op, a, b;
        fin >> op >> a >> b;
        if (op == 0)
            fout << Query(1, 1, N, a, b) << "\n";
        else if (op == 1)
            Update(1, 1, N, a, b);
    }
    return 0;
}