二叉树层序遍历BFS

leetcode 刷题记录
层序遍历模板,语言为 golang

func bfs(p *TreeNode) []int {
    res := make([]int, 0)
    if p == nil {
        return res
    }
    queue := []*TreeNode{p}
    for len(queue) > 0 {
        length := len(queue)
        for length > 0 {
            length--
            if queue[0].Left != nil {
                queue = append(queue, queue[0].Left)
            }
            if queue[0].Right != nil {
                queue = append(queue, queue[0].Right)
            }
            res = append(res, queue[0].Val)
            queue = queue[1:]
        }
    }
    return res
}