题解 | #对称的二叉树#

/*
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public boolean isSymmetrical(TreeNode pRoot) {
        if (pRoot == null)
            return true;
        return is(pRoot.left, pRoot.right);
    }

    public boolean is(TreeNode left, TreeNode right) {
        if (left == null && right == null) {
            return true;
        } else if (left == null || right == null)
            return false;
        if (left.val != right.val)
            return false;
        else {
            return is(left.left, right.right) && is(left.right, right.left);
        }
    }
}