题解 | #按之字形顺序打印二叉树#

按之字形顺序打印二叉树

https://www.nowcoder.com/practice/91b69814117f4e8097390d107d2efbe0

双端队列
/*
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) {
        vector<vector<int>> ret;
        if (pRoot == nullptr) {
            return ret;
        }
        deque<TreeNode*> treeDeque;
        treeDeque.push_back(pRoot);
        int direction = 1;
        while (!treeDeque.empty()) 
        {
            int num = treeDeque.size();
            vector<int> lineData;
            for (int i = 0; i < num; ++i) 
            {
                if (direction)
                {
                    TreeNode* temNode = treeDeque.front();
                    treeDeque.pop_front();
                    if(temNode->left)
                    {
                        treeDeque.push_back(temNode->left);
                    }
                    if(temNode->right)
                    {
                        treeDeque.push_back(temNode->right);
                    }
                    lineData.push_back(temNode->val);
                } 
                else 
                {
                    TreeNode* temNode=treeDeque.back();
                    treeDeque.pop_back();
                    if(temNode->right)
                    {
                        treeDeque.push_front(temNode->right);
                    }
                    if(temNode->left)
                    {
                        treeDeque.push_front(temNode->left);
                    }
                    lineData.push_back(temNode->val);
                }
            }
            ret.emplace_back(lineData);
            direction=direction==1?0:1;
        }
        return ret;

    }

};


全部评论

相关推荐

北漂的牛马人:211佬,包进的,可能是系统问题
点赞 评论 收藏
分享
不愿透露姓名的神秘牛友
07-07 13:35
虽然不怎么光彩,经过这件事,可能我真的要去认同“面试八股文早该淘汰!不会用AI作弊的程序员=新时代文盲!”这句话了
HellowordX:Ai的出现是解放劳动力的,不是用来破坏公平竞争环境的,这样下去,轻则取消所有线上面试,严重了会影响整个行业对所有人产生影响,企业会拉高入职考核各种离谱考核会层出不穷
你找工作的时候用AI吗?
点赞 评论 收藏
分享
评论
点赞
收藏
分享

创作者周榜

更多
牛客网
牛客网在线编程
牛客网题解
牛客企业服务