Cod sursa(job #3135759)

Utilizator yungxristfaur cristian yungxrist Data 4 iunie 2023 12:50:36
Problema Arbori de intervale Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.73 kb
#include <bits/stdc++.h>
#include <fstream>

using namespace std;
ifstream in("arbint.in.txt");
ofstream out("arbint.out.txt");

const int N_MAX = 100000;

int tree[4 * N_MAX + 5];
int V[N_MAX + 5];

void build(int node, int le, int ri) 
{
    if(le == ri) 
    {
        tree[node] = V[le];
        return;
    }
    int mid = (le + ri) / 2;

    build(2 * node, le, mid);
    build(2 * node + 1, mid + 1, ri);

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

void update(int node, int le, int ri, int pos, int val) 
{
    if(le == ri) 
    {
        tree[node] = val;
        return;
    }
    
    int mid = (le + ri) / 2;

    if(pos <= mid) 
    {
        update(2 * node, le, mid, pos, val);
    }
    else 
    {
        update(2 * node + 1, mid + 1, ri, pos, val);
    }

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

void query(int node, int le, int ri, int x, int y, int &ans) 
{
    if(x <= le && ri <= y) 
    {
        ans = max(ans, tree[node]);
        return;
    }

    int mid = (le + ri) / 2;

    if(x <= mid) 
    {
        query(2 * node, le, mid, x, y, ans);
    }
    if(y > mid) 
    {
        query(2 * node + 1, mid + 1, ri, x, y, ans);
    }
}

int main() 
{
    int n, m, x, a, b, maxim;
    in >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        in >> V[i];
    }
    build(1, 1, n);
    for (int i = 1; i <= m; i++)             //x operatie a,b interval
    {
        in >> x >> a >>b;
        if (x == 0)
        {
            maxim = -100000000;
            query(1, 1, n, a, b, maxim);
            out << maxim << '\n';
        }
        if (x == 1)
        {
            update(1, 1, n, a, b);
        }

    }

}