Cod sursa(job #2771215)

Utilizator AlexZeuVasile Alexandru AlexZeu Data 26 august 2021 10:27:04
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.37 kb
#include <bits/stdc++.h>
using namespace std;

vector<int> tree;

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

void update(int pos, int node, int left, int right, int value) {
    if (left == right) {
        tree[node] = value;
        return;
    }
    int mij = (left + right) / 2;
    if (pos <= mij) {
        update(pos, 2 * node, left, mij, value);
    } else {
        update(pos, 2 * node + 1, mij + 1, right, value);
    }
    tree[node] = max(tree[2 * node], tree[2 * node + 1]);
}

void query(int node, int a, int b, int left, int right, int &maxim) {
    if (left >= a && right <= b) {
        maxim = max(maxim, tree[node]);
        return;
    }
    int mij = (left + right) / 2;
    if (mij >= a) {
        query(2 * node, a, b, left, mij, maxim);
    }
    if (mij < b) {
        query(2 * node + 1, a, b, mij + 1, right, maxim);
    }
}

int main() {
    ios::sync_with_stdio(false), fin.tie(nullptr);
    int N, M; fin >> N >> M;
    tree.resize(4 * N);
    for (int i = 0; i < N; ++i) {
        int x; fin >> x;
        update(i, 1, 0, N - 1, x);
    }
    while(M--) {
        int cer, a, b; fin >> cer >> a >> b;
        if (cer == 1) {
            --a;
            update(a, 1, 0, N - 1, b); 
        } else {
            int maxim = -1;
            --a, --b;
            query(1, a, b, 0, N - 1, maxim);
            fout << maxim << '\n';
        }
    }
    return 0;
}