Cod sursa(job #3369648)

Utilizator Alex_Belu_2009Belu Alexandru Alex_Belu_2009 Data 21 octombrie 2026 12:12:55
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.43 kb
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100000;
int v[MAXN + 1];
int tree[4 * MAXN + 5];
void build(int node, int l, int r) {
    if (l == r) {
        tree[node] = v[l];
        return;
    }
    int mid = (l + r) / 2;
    build(node * 2, l, mid);
    build(node * 2 + 1, mid + 1, r);
    tree[node] = max(tree[node * 2],tree[node * 2 + 1]);
}
int query(int node, int l, int r, int a, int b) {
    if (b < l || r < a)
        return 0;
    if (a <= l && r <= b)
        return tree[node];
    int mid = (l + r) / 2;
    return max(query(node * 2, l, mid, a, b),query(node * 2 + 1, mid + 1, r, a, b));
}
void update(int node, int l, int r, int pos, int val) {
    if (l == r) {
        tree[node] = val;
        return;
    }
    int mid = (l + r) / 2;
    if (pos <= mid)
        update(node * 2, l, mid, pos, val);
    else
        update(node * 2 + 1, mid + 1, r, pos, val);
    tree[node] = max(
        tree[node * 2],
        tree[node * 2 + 1]
    );
}
int main() {
    ifstream fin("arbint.in");
    ofstream fout("arbint.out");
    int n, m;
    fin >> n >> m;
    for (int i = 1; i <= n; i++)
        fin >> v[i];
    build(1, 1, n);
    for (int i = 0; i < m; i++) {
        int op, a, b;
        fin >> op >> a >> b;
        if (op == 0) {
            fout << query(1, 1, n, a, b) << '\n';
        } else {
            update(1, 1, n, a, b);
        }
    }
    return 0;
}