100. Same Tree

/** * 100. Same Tree *  * Problem Description: * 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.  *  * Definition for a binary tree node. * 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) return false;        if(p.val == q.val)            return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);        return false;    }}