Hacktoberfestmine/Count_BST_nodes_that_lie_in_a_given_range.cpp at main · pythonites/Hacktoberfestmine · GitHub

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#include <bits/stdc++.h>
using namespace std;

struct Node {
    int data;
    Node* right;
    Node* left;

    Node(int x) {
        data = x;
        right = NULL;
        left = NULL;
    }
};


Node *insert(Node *root, int data)
{
    if (root == NULL)
        root = new Node(data);
    else if (data < root->data)
        root->left = insert(root->left, data);
    else
        root->right = insert(root->right, data);

    return root;
}

/*
structure of a BST node:
*/
struct Node {
    int data;
    Node* right;
    Node* left;

    Node(int x) {
        data = x;
        right = NULL;
        left = NULL;
    }
};


int getCountOfNode(Node *root, int l, int h)
{

    if (root == NULL)
        return 0;
    if (root->data == l && root->data == h)
        return 1;
    if (root->data <= h && root->data >= l)
        return 1 + getCountOfNode(root->left, l, h) + getCountOfNode(root->right, l, h);
    else if (root->data < l)
        return getCountOfNode(root->right, l, h);
    else if (root->data > h)
        return getCountOfNode(root->left, l, h);
}


int main() {

    int t;
    cin >> t;
    while (t--)
    {
        Node *root = NULL;
        int n;
        cin >> n;
        int arr[n];

        for (int i = 0; i < n; i++)
            cin >> arr[i];

        for (int i = 0; i < n; i++)
        {
            root = insert(root, arr[i]);
        }
        int l, h;
        cin >> l >> h;
        cout << getCountOfNode(root, l, h) << endl;
    }
    return 0;
}