Same Tree

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes 

have the same value.

public class Solution {    public boolean isSameTree(TreeNode p, TreeNode q) {       if(p==null&&q==null)    return true;    else if(p==null||q==null)        return false;    return p.val==q.val&&isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);    }}