剑指 Offer 32 - II. 从上到下打印二叉树 II

最新推荐文章于 2022-07-17 22:06:33 发布

爬比我。

最新推荐文章于 2022-07-17 22:06:33 发布

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/**
 * 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) {
    vector<vector<int>> v;
    if(root==NULL)
        return v;

    queue<TreeNode*> ret;
    ret.push(root);
    v.push_back({root->val});
    while(!ret.empty())
    {
        queue<TreeNode*> temp;
        vector<int> s;
        while(!ret.empty())
        {
            if(ret.front()->left!=NULL)
            {  
                temp.push(ret.front()->left);
                s.push_back(ret.front()->left->val);
            }
            if(ret.front()->right!=NULL)
            {
                temp.push(ret.front()->right);
                s.push_back(ret.front()->right->val);
            }
            ret.pop();
        }

        if(!s.empty())
        {v.push_back(s);}
        ret=temp;
    }
    return v;
    }
};