题解 | #按之字形顺序打印二叉树#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
#include <algorithm>
#include <deque>
#include <queue>
#include <vector>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return int整型vector<vector<>>
     */
    vector<vector<int> > Print(TreeNode* pRoot) {
        // write code here
        if (pRoot == nullptr) {
            return m_retVal;
        }
        bool flag = true;
        queue<TreeNode*> qu;
        qu.push(pRoot);
        while (!qu.empty()) {
            vector<int> tempVec;
            int size = qu.size();
            for (int i = 0; i < size; ++i) {
                TreeNode* tempNode = qu.front();
                tempVec.push_back(tempNode->val);
                qu.pop();
                if (tempNode->left) {
                    qu.push(tempNode->left);
                }
                if (tempNode->right) {
                    qu.push(tempNode->right);
                }
            }
            if (!flag) {
                reverse(tempVec.begin(), tempVec.end());
            }
            flag = !flag;
            m_retVal.push_back(tempVec);
        }
        return m_retVal;
    }
private:
    std::vector<vector<int>> m_retVal;
};