Dynamic Range Minimum Queries

input/code.cpp: In function 'std::vector<int> create_segment_tree(std::vector<int>&, int)':
input/code.cpp:53:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |     for (int i = 0; i < values.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

vector<int> create_segment_tree(vector<int> &values, int n);
void update_segment_tree(vector<int> &seg_tree, int i, int u, int n);
int query_segment_tree(vector<int> &seg_tree, int a, int b, int n);
int next_power_2(int x);
void print_vector(vector<int> &x);

// approach: SegmentTrees
int main()
{
    int n, q;
    cin >> n >> q;
    vector<int> values(n);

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

    int seg_tree_n = next_power_2(n);
    vector<int> seg_tree = create_segment_tree(values, seg_tree_n);

    for (int i = 0; i < q; i++)
    {
        int type;
        cin >> type;

        if (type == 1)
        {
            int k, u;
            cin >> k >> u;
            k--;
            update_segment_tree(seg_tree, k, u, seg_tree_n);
        }
        else
        {
            int a, b;
            cin >> a >> b;
            a--;
            b--;
            int query_result = query_segment_tree(seg_tree, a, b, seg_tree_n);
            cout << query_result << "\n";
        }
    }
}

vector<int> create_segment_tree(vector<int> &values, int n)
{
    vector<int> seg_tree(2 * n, INT32_MAX);
    for (int i = 0; i < values.size(); i++)
    {
        seg_tree[n + i] = values[i];
    }
    for (int i = n - 1; i > 0; i--)
    {
        seg_tree[i] = min(seg_tree[2 * i], seg_tree[2 * i + 1]);
    }
    return seg_tree;
}

void update_segment_tree(vector<int> &seg_tree, int i, int u, int n)
{
    // print_vector(seg_tree);
    int k = i + n;
    // cout << "i: " << i << " - u: " << u << " - n: " << n << " - k: " << k << endl;
    seg_tree[k] = u;
    for (k /= 2; k >= 1; k /= 2)
    {
        // cout << "k: " << k << endl;
        // print_vector(seg_tree);
        seg_tree[k] = min(seg_tree[2 * k], seg_tree[2 * k + 1]);
    }
}

int query_segment_tree(vector<int> &seg_tree, int a, int b, int n)
{
    a += n;
    b += n;
    int result = INT32_MAX;
    while (a <= b)
    {
        if (a % 2 == 1)
        {
            result = min(result, seg_tree[a--]);
        }
        if (b % 2 == 0)
        {
            result = min(result, seg_tree[b--]);
        }
        a /= 2;
        b /= 2;
    }
    return result;
}

int next_power_2(int x)
{
    // int exponent = ceil(log2(x));
    // return pow(2, exponent);
    int power_2 = 1;
    while (power_2 <= x)
    {
        power_2 = power_2 << 1;
    }
    return power_2;
}

void print_vector(vector<int> &x)
{
    for (int v : x)
    {
        cout << v << " ";
    }
    cout << "\n";
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER