剑指offer 按之字形顺序打印二叉树&把二叉树打印成多行

题目描述
请实现一个函数按照之字形打印二叉树，即第一行按照从左到右的顺序打印，第二层按照从右至左的顺序打印，第三行按照从左到右的顺序打印，其他行以此类推。

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
    vector<vector<int> > Print(TreeNode* pRoot) {
        stack<TreeNode*> oneLevel;
        vector<vector<int> > res;
        if(pRoot==NULL) {
            return res;
        }
        oneLevel.push(pRoot);
        
        while(!oneLevel.empty()) {
            vector<int> thisLevelElement;
            stack<TreeNode*> nextLevel;
            while (!oneLevel.empty())   
            {
                TreeNode* temp=oneLevel.top();
                thisLevelElement.push_back(temp->val);
                if(res.size()%2==0) {
                    if(temp->left!=NULL) {
                        nextLevel.push(temp->left);
                    }
                    if(temp->right!=NULL) {
                        nextLevel.push(temp->right);
                    }
                } else {
                    if(temp->right!=NULL) {
                        nextLevel.push(temp->right);
                    }
                    if(temp->left!=NULL) {
                        nextLevel.push(temp->left);
                    }
                }
                
                oneLevel.pop();
            }
            res.push_back(thisLevelElement);
            oneLevel=nextLevel;
        }
        return res;
    }
};

题目描述
从上到下按层打印二叉树，同一层结点从左至右输出。每一层输出一行。

class Solution {
public:
    vector<vector<int> > Print(TreeNode* pRoot) {
        queue<TreeNode*> oneLevel;
        vector<vector<int> > res;
        if(pRoot==NULL) {
            return res;
        }
        oneLevel.push(pRoot);
        
        while(!oneLevel.empty()) {
            vector<int> thisLevelElement;
            queue<TreeNode*> nextLevel;
            while (!oneLevel.empty())   
            {
                TreeNode* temp=oneLevel.front();
                thisLevelElement.push_back(temp->val);

                    if(temp->left!=NULL) {
                        nextLevel.push(temp->left);
                    }
                    if(temp->right!=NULL) {
                        nextLevel.push(temp->right);
                    }
                oneLevel.pop();
            }
            res.push_back(thisLevelElement);
            oneLevel=nextLevel;
        }
        return res;
    }
};