【LeetCode】Same Tree

http://oj.leetcode.com/problems/same-tree/

public class Solution {
    
    public boolean isSameTree(TreeNode p, TreeNode q) {
        Stack<TreeNode> pstack = new Stack<TreeNode>();
        Stack<TreeNode> qstack = new Stack<TreeNode>();
        if(null==p&&null==q){
            return true;
        }
        if(null==p||null==q){
            return false;
        } else {
            while(!pstack.isEmpty()||!qstack.isEmpty()||p!=null||q!=null){
                if(p!=null&&q!=null){
                    if(p.val!=q.val){
                        return false;
                    }
                    pstack.push(p);
                    qstack.push(q);
                    p=p.left;
                    q=q.left;
                    if(q==null&&p!=null)
                        return false;
                    if(p==null&&q!=null)
                        return false;
                    
                }else{
                    p=pstack.peek().right;
                    pstack.pop();
                    q=qstack.peek().right;
                    qstack.pop();
                }
                
            }
            return true;
        }
        
        
        
    }
}