Joey LIU | NANTSOU


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class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (root == null || root == p || root == q) {
            return root;
        }
        TreeNode l = lowestCommonAncestor(root.left, p, q);
        TreeNode r = lowestCommonAncestor(root.right, p, q);
        if (l != null && r != null) {
            return root;
        } else {
            if (l != null) {
                return l;
            } else if (r != null) {
                return r;
            } else {
                return null;
            }
        }
    }
}