Lowest Common Ancestor III Lintcode

class Result {
    boolean foundA;
    boolean foundB;
    TreeNode root;
    public Result(boolean a, boolean b, TreeNode root) {
        foundA = a;
        foundB = b;
        this.root = root;
    }
}

public class Solution {
    /**
     * @param root The root of the binary tree.
     * @param A and B two nodes
     * @return: Return the LCA of the two nodes.
     */
    public TreeNode lowestCommonAncestor3(TreeNode root, TreeNode A, TreeNode B) {
        Result rs = helper(root, A, B);
        if (rs.foundA && rs.foundB) {
            return rs.root;
        }
        return null;
    }
    public Result helper(TreeNode root, TreeNode A, TreeNode B) {
        if (root == null) {
            return new Result(false, false, null);
        }
        
        Result left = helper(root.left, A, B);
        Result right = helper(root.right, A, B);
        
        boolean a = left.foundA || right.foundA || root == A;
        boolean b = left.foundB || right.foundB || root == B;
        
        if (root == A || root == B) {
            return new Result(a, b, root);
        }
        if (left.root != null && right.root != null) {
            return new Result(a, b, root);
        }
        if (left.root != null) {
            return new Result(a, b, left.root);
        }
        if (right.root != null) {
            return new Result(a, b, right.root);
        }
        return new Result(a, b, null);
    }
}