Cod sursa(job #2771202)

Utilizator AlexZeuVasile Alexandru AlexZeu Data 26 august 2021 08:53:26
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.35 kb
#include <bits/stdc++.h>
using namespace std;

const int mxN = 1e5 + 5;

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

int MaxArb[4 * mxN];

void update(int pos, int node, int left, int right, int value) {
    if (left == right) {
        MaxArb[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);
    }
    MaxArb[node] = max(MaxArb[2 * node], MaxArb[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, MaxArb[node]);
        return;
    }
    int mij = (left + right) / 2;
    if (a <= mij) {
        Query(2 * node, a, b, left, mij, maxim);
    }
    if (b > mij) {
        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;
    for (int i = 1; i <= N; ++i) {
        int x; fin >> x;
        update(i, 1, 1, N, x);
    }
    while (M--) {
        int cerinta, a, b; fin >> cerinta >> a >> b;
        if (cerinta == 0) {
            int maxim = -1;
            Query(1, a, b, 1, N, maxim);
            fout << maxim << '\n';
        } else {
            update(a, 1, 1, N, b);
        }
    }
    return 0;
}