【leetcode】429.N 叉树的层序遍历

leetcode-429.png

也是典型的BFS题目，搞清楚数据结构就好处理了

BFS

var levelOrder = function (root) {
    if (!root) return []
    let res = []
    let queue = []
    queue.push(root)
    while (queue.length) {
        let size = queue.length
        let level = []
        for (let i = 0; i < size; ++i) {
            let node = queue.shift()
            level.push(node.val)
            if (node.children) {
                queue.push(...node.children)
            }
        }
        res.push(level)
    }
    return res
};