Leetcode #236 Lowest Common Ancestor of a Binary Tree

[yokostan]

Recursive:

class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (root == null) return null;

        if (root == p || root == q) return root;

        TreeNode left = lowestCommonAncestor(root.left, p, q);
        TreeNode right = lowestCommonAncestor(root.right, p, q);

        if (left != null && right != null) return root;
        if (left != null) return left;
        if (right != null) return right;

        return null;
    }
}