Dynamic Range Minimum Queries

input/code.cpp: In function 'int main()':
input/code.cpp:50:32: error: 'log2' was not declared in this scope
   50 |     int elems = 1 << (int)ceil(log2(n));
      |                                ^~~~
input/code.cpp:50:27: error: 'ceil' was not declared in this scope
   50 |     int elems = 1 << (int)ceil(log2(n));
      |                           ^~~~

#include <iostream>
#include <vector>
#include <ranges>
using namespace std;

int parent(int node) {
    return node / 2;
}

int left(int node) {
    return 2 * node;
}

int right(int node) {
    return 2 * node + 1;
}

int getMin(int a, int b, vector<int>& arr) {
    int n = arr.size() / 2;
    a += n; b += n;
    int minVal = 1e9+1;
    while (a <= b) {
        if (a%2 == 1) {
            minVal = min(minVal, arr[a]);
            a++;
        }
        if (b%2 == 0) {
            minVal = min(minVal, arr[b]);
            b--;
        }
        a = parent(a);
        b = parent(b);
    }
    return minVal;
}

void setVal(int ind, int val, vector<int>& arr) {
    int n = arr.size() / 2;
    ind += n;
    arr[ind] = val;
    for (ind /= 2; ind >= 1; ind /= 2) {
        arr[ind] = min(arr[left(ind)], arr[right(ind)]);
    }
}

int main() {
    int n, q;
    cin >> n >> q;

    int elems = 1 << (int)ceil(log2(n));
    vector<int> tree(2*elems);

    for (int i=0; i<n; i++) {
        cin >> tree[i + elems];
    }

    for (int i=n; i<elems; i++) {
        tree[i + elems] = 1e9+1;
    }

    for (int i=elems-1; i>0; i--) {
        tree[i] = min(tree[left(i)], tree[right(i)]);
    }

    int op, i1, i2;
    for (int i=0; i<q; i++) {
        cin >> op >> i1 >> i2;
        if (op == 1) {
            setVal(i1-1, i2, tree);
        }
        else if (op == 2) {
            cout << getMin(i1-1, i2-1, tree) << endl;
        }
    }

    return 0;
}