Dynamic Range Minimum Queries

#include <iostream>
#include <vector>
#include <algorithm>
#include <climits> // Include this for INT_MAX

using namespace std;

class SegmentTree {
public:
    int n;
    vector<int> tree;

    // Constructor to initialize the segment tree
    SegmentTree(const vector<int>& data) {
        n = data.size();
        tree.resize(2 * n);
        build(data);
    }

    // Build the segment tree from the input data
    void build(const vector<int>& data) {
        // Insert leaf nodes in the tree
        for (int i = 0; i < n; ++i) {
            tree[n + i] = data[i];
        }
        // Build the tree by calculating parents
        for (int i = n - 1; i > 0; --i) {
            tree[i] = min(tree[2 * i], tree[2 * i + 1]);
        }
    }

    // Update the value at position index to value
    void update(int index, int value) {
        index += n;
        tree[index] = value;
        while (index > 1) {
            index /= 2;
            tree[index] = min(tree[2 * index], tree[2 * index + 1]);
        }
    }

    // Query the minimum value in range [left, right]
    int query(int left, int right) {
        left += n;
        right += n + 1;
        int result = INT_MAX;
        while (left < right) {
            if (left % 2 == 1) {
                result = min(result, tree[left]);
                ++left;
            }
            if (right % 2 == 1) {
                --right;
                result = min(result, tree[right]);
            }
            left /= 2;
            right /= 2;
        }
        return result;
    }
};

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

    int n, q;
    cin >> n >> q;

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

    SegmentTree segTree(data);

    for (int i = 0; i < q; ++i) {
        int type;
        cin >> type;
        if (type == 1) {
            int k, u;
            cin >> k >> u;
            segTree.update(k - 1, u);
        } else if (type == 2) {
            int a, b;
            cin >> a >> b;
            cout << segTree.query(a - 1, b - 1) << '\n';
        }
    }

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED