LeetCode / Tree / 102번 / Binary Tree Level Order Traversal / JS

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Binary Tree Level Order Traversal - LeetCode

 

< 문제 간단설명 >

Level Order, 즉 한 Level(=depth)씩 탐색하는 문제이다. BFS와 같다.

 

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number[][]}
 */
var levelOrder = function(root) {
    if(root === null) return [];

    let result = [];
    let queue = [];
    queue.push(root);

    while(queue.length) {
        let level = [];
        let len = queue.length;

        for(let i=0; i<len; i+=1) {
            let node = queue.shift();

            level.push(node.val);
            node.left ? queue.push(node.left) : null;
            node.right ? queue.push(node.right) : null;
        }

        result.push(level);
    }

    return result;
};