Cod sursa(job #2574380)

Utilizator nTropicManescu Bogdan Constantin nTropic Data 5 martie 2020 21:55:17
Problema Arbori de intervale Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.3 kb
#include <bits/stdc++.h>

using namespace std;

const int len = 100005;
int n, m, x, key, a, b, tree[4 * len];

void update(int val, int pos, int node = 1, int left = 1, int right = n) {
    if (left == right) {
        tree[node] = val;
        return;
    }

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

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

int query(int a, int b, int node = 1, int left = 1, int right = n) {
    if (a <= left && b >= right)
        return tree[node];

    int mid = (left + right) / 2, res = 0;
    if (a <= mid)
        res = max(res, query(a, b, node * 2, left, mid));
    else if (b > mid)
        res = max(res, query(a, b, node * 2 + 1, mid + 1, right));

    return res;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);

    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> x;
        update(x, i);
    }
    for (int i = 1; i <= m; i++) {
        cin >> key >> a >> b;
        if (key)
            update(b, a);
        else
            cout << query(a, b) << "\n";
    }
}