Cod sursa(job #2817659)

Utilizator Andrei_Tud1Andrei Tudorache Andrei_Tud1 Data 13 decembrie 2021 23:19:26
Problema Arbori de intervale Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.92 kb
#include <iostream>
#include <fstream>

using namespace std;

int arbint[400001], v[100001];

ifstream fin("arbint.in");
ofstream fout("arbint.out");
void build(int node, int left, int right)
{
    if(left == right)
        arbint[node] = v[left];
    else
    {
        int mid = (left + right) / 2;

        build(node * 2, left, mid);
        build(node * 2 + 1, mid + 1, right);

        arbint[node] = max(arbint[node * 2], arbint[node * 2 + 1]);
    }
}

void update(int node, int left, int right, int poz, int val)
{
    if(left == right)
        arbint[node] = val;
    else
    {
        int mid = (left + right) / 2;

        if(poz <= mid)
            update(node * 2, left, mid, poz, val);
        else
            update(node * 2 + 1, mid + 1, right, poz, val);

        arbint[node] = max(arbint[node * 2], arbint[node * 2 + 1]);
    }
}

int query(int node, int left, int right, int query_left, int query_right)
{
    if(query_left <= left  && right <= query_right)
        return arbint[node];
    else
    {
        int mid = (left + right) / 2;

        if(query_right <= mid)
            return query(node * 2, left, mid, query_left, query_right);
        if(query_left >= mid+1)
            return query(node * 2 + 1, mid + 1, right, query_left, query_right);

        return max(query(node * 2, left, mid, query_left, query_right), query(node * 2 + 1, mid + 1, right, query_left, query_right));
    }
}

int main()
{
    int n, m;
    fin >> n >> m;

    for(int i = 1; i <= n; i++)
        fin >> v[i];

    build(1, 1, n);

    while(m)
    {
        bool o;
        int a, b;
        fin >> o;
        if(o == 0)
        {
            fin >> a >> b;
            fout << query(1, 1, n, a, b) << endl;
        }
        else if(o == 1)
        {
            fin >> a >> b;
            update(1, 1, n, a, b);
        }
        m--;
    }
    return 0;
}