LowestCommonAncestorOfBinaryTree.java

// https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree
// T: O(N)
// S: O(log(N))

public class LowestCommonAncestorOfBinaryTree {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (root == null || 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;
        return left == null ? right : left;
    }
}