int val = 0;

TreeNode left = null;

TreeNode right = null;

public TreeNode(int val) {

this.val = val;

}

boolean isSymmetrical(TreeNode pRoot)

{

if (pRoot == null) {

return true;

}

return symmetrical(pRoot.left, pRoot.right);

}

public boolean symmetrical(TreeNode aTree, TreeNode bTree) {

if (aTree == null && bTree == null) {

return true;

}

if ( (aTree != null && bTree == null) || (aTree == null && bTree != null) ) {

return false;

}

if (aTree.val != bTree.val) {

return false;

}

return symmetrical(aTree.left, bTree.right) && symmetrical(aTree.right, bTree.left);

}

}