codeDump/cpp/LowestCommonAncestorInBinarySearchTree.cpp at main · akkupy/codeDump · GitHub

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// https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/description/

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {

        while(root!=NULL) {
            if(root->val<p->val && root->val<q->val)
                root= root->right;
            else if (root->val>p->val && root->val>q->val)
                root= root->left;
            else
                break;
        }

        return root;

        // Recursive Approach
        // if(root==NULL)
        //     return NULL;

        // if(root->val<p->val && root->val<q->val)
        //     return lowestCommonAncestor(root->right, p, q);
        // else if (root->val>p->val && root->val>q->val)
        //     return lowestCommonAncestor(root->left, p, q);
        // else
        //     return root;
    }
};