LeetCode Binary Tree Zigzag Level Order Traversal

 //应该用两个栈  16ms
 1 /**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int> > zigzagLevelOrder(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<int> v;
        vector<vector<int> > re;
        stack<TreeNode >s;
        deque<TreeNode >q;
        TreeNode t(0);
        if(root==NULL)
        {
            return re;
        }
        q.push_back(*root);
        while(!q.empty())
        {
            v.clear();
            while(!q.empty())
            {
                t=q.front();
                v.push_back(t.val);
                q.pop_front();
                
                if(t.left)
                    s.push(*(t.left));
                if(t.right)
                    s.push(*(t.right));
                
            }
            re.push_back(v);
            v.clear();
            while(!s.empty())
            {
                t=s.top();
                v.push_back(t.val);
                s.pop();               
                
                if(t.right)
                    q.push_front(*(t.right));
                if(t.left)
                    q.push_front(*(t.left));
                
            }
            if(v.size())
                re.push_back(v);
            v.clear();
        }
        return re;
    }
    
    
    
    
    
    
    
    
    
};