c/c++语言开发共享剑指offer59：按之字形顺序打印二叉树：[[1], [3,2], [4,5,6,7]]

 1 /*   2 struct treenode {   3     int val;   4     struct treenode *left;   5     struct treenode *right;   6     treenode(int x) :   7             val(x), left(null), right(null) {   8     }   9 };  10 */  11 class solution {  12 public:  13     vector<vector<int> > print(treenode* proot) {  14         vector<vector<int>> result;  15         if(proot==nullptr)  16             return result;  17         stack<treenode*> stack1,stack2;//分别存奇数和偶数层  18         stack1.push(proot);  19         while(!stack1.empty() || !stack2.empty()){  20             if(!stack1.empty()){  21                 vector<int> temp;  22                 while(!stack1.empty()){  23                     treenode *data=stack1.top();  24                     stack1.pop();  25                     temp.push_back(data->val);  26                     if(data->left!=nullptr)  27                         stack2.push(data->left);  28                     if(data->right!=nullptr)  29                         stack2.push(data->right);  30                 }  31                 result.push_back(temp);  32             }  33             if(!stack2.empty()){  34                 vector<int> temp;  35                 while(!stack2.empty()){  36                     treenode *data=stack2.top();  37                     stack2.pop();  38                     temp.push_back(data->val);  39                     if(data->right!=nullptr)  40                         stack1.push(data->right);  41                     if(data->left!=nullptr)  42                         stack1.push(data->left);  43                 }  44                 result.push_back(temp);  45             }  46         }  47         return result;  48     }  49 };