Notice
Recent Posts
«   2022/12   »
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31
Tags more
Archives
Today
0
Total
195
관리 메뉴

## [leetCode/JS] 222. Count Complete Tree Nodes 본문

coding test/leetCode

### [leetCode/JS] 222. Count Complete Tree Nodes

쭘봉 2022. 11. 23. 11:07

### 문제 설명

Given the root of a complete binary tree, return the number of the nodes in the tree.

According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclusive at the last level h.

Design an algorithm that runs in less than O(n) time complexity.

### 입출력 예

#### Example 1:

Input: root = [1,2,3,4,5,6]
Output: 6

Input: root = []
Output: 0

#### Example 3:

Input: root = [1]
Output: 1

### Constraints

• The number of nodes in the tree is in the range [0, 5 * 104].
• 0 <= Node.val <= 5 * 104
• The tree is guaranteed to be complete.

## 내 솔루션

• 어제 DFS, BFS 같은 알고리즘 공부를 해두어서 쉬운 문제였다.
var countNodes = function(root) {
let count = 0;
const search = (root) => {
if(!root) return
count++;
search(root.left)
search(root.right)
}

search(root)
return count
};

## 감상평

• 복잡하게 count 값을 리턴하는 형태로 할 수 있지만 그럼 귀찮기 때문에 전역으로 처리..

#### 'coding test > leetCode' 카테고리의 다른 글

[leetCode/JS] 1700. Number of Students Unable to Eat Lunch  (0) 2022.11.23 2022.11.23 2022.11.23 2022.11.22 2022.11.22