[LeetCode] Grind 75 questions (10/75) Lowest Common Ancestor of a Binary Search Tree

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/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */

class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if(root.val > p.val && root.val > q.val) {
            // root보다 값이 작을 경우
            return lowestCommonAncestor(root.left, p, q);
        } else if(root.val < p.val && root.val < q.val) {
            // root보다 값이 클 경우
            return lowestCommonAncestor(root.right, p, q);
        } else {
            // TreeNode p와 q가 같은 노드에 없다면 root가 부모다
            return root;
        }
    }
}