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leet code

931 - Binary Tree Level Order Traversal

시간, 공간 둘다 나쁘지 않았습니다.

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#include<queue>
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    vector<vector<int>> levelOrder(TreeNode* root) {
        queue<TreeNode*> q;
        TreeNode* tmp;
        q.push(root);

        vector<vector<int>> rslt;

        if(!root) return rslt;

        while(q.size())
        {
            vector<int> cur_tmp;
            int qSize = q.size();
            for(int i=0; i<qSize; ++i)
            {
                tmp = q.front();
                q.pop();

                if(tmp) cur_tmp.push_back(tmp->val);
                if(tmp->left) q.push(tmp->left);
                if(tmp->right) q.push(tmp->right);
            }
            rslt.push_back(cur_tmp);
        }

        return rslt;
    }
};