/*

public class TreeNode {

    int val = 0;

    TreeNode left = null;

    TreeNode right = null;

    public TreeNode(int val) {

        this.val = val;

    }

}

*/

public class Solution {

   boolean isSymmetrical(TreeNode pRoot)

    {

        if(pRoot==null)

            return true;

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

    }

    boolean isSymmetricalCore(TreeNode pRoot1,TreeNode pRoot2)

    {

        if(pRoot1==null&&pRoot2==null)

            return true;

        if(pRoot1==null||pRoot2==null)

            return false;

        if(pRoot1.val!=pRoot2.val)

            return false;

        return isSymmetricalCore(pRoot1.left,pRoot2.right)&&isSymmetricalCore(pRoot1.right,pRoot2.left);

    }

}