[数据结构与算法]【剑指offer】剑指 Offer 32 - III. 从上到下打印二叉树 III

题目链接

剑指 Offer 32 - III. 从上到下打印二叉树 III

思路分析

代码实现

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int>> levelOrder(TreeNode* root) {
        bool flag = true;
        vector<vector<int>> ret;
        queue<TreeNode*> q;
        if(root != NULL)
            q.push(root);
        while(!q.empty())
        {
            int sz = q.size();
            vector<int> path;
            for(int i = 0; i < sz; ++i)
            {
                TreeNode* node = q.front();
                path.push_back(node->val);
                q.pop();
                if(node->left)
                    q.push(node->left);
                if(node->right)
                    q.push(node->right);
            }
            if(!flag)
            {
                reverse(path.begin(), path.end());
            }
            flag = !flag;
            ret.push_back(path);
        }
        return ret;
    }
};