/** * Definition for binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean isSameTree(TreeNode p, TreeNode q) {        if(p == null && q == null)            return true;        if(p!= null && q != null){            if(p.val == q.val){                boolean x = isSameTree(p.left,q.left);                boolean y = isSameTree(p.right,q.right);                return x==true && y==true;            }        }        return false;    }}