Java判断两个二叉树是否相同

</pre><pre name="code" class="java">class TreeNode
{
int val;
TreeNode left
TreeNode right;
public TreeNode(int val){
this.val=val;
}
}
public boolean isSameTree(TreeNode p,TreeNode q){
if(p==null&&q==null){
return true;
}
if(p!=null&&q==null){
return false;
}
if(p==null&&q!=null){
return false;
}
if(p.val!=q.val){
return false;
}
return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
}