Solution.go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func averageOfLevels(root *TreeNode) []float64 {
	q := []*TreeNode{root}
	ans := []float64{}
	for len(q) > 0 {
		n := len(q)
		s := 0
		for i := 0; i < n; i++ {
			root = q[0]
			q = q[1:]
			s += root.Val
			if root.Left != nil {
				q = append(q, root.Left)
			}
			if root.Right != nil {
				q = append(q, root.Right)
			}
		}
		ans = append(ans, float64(s)/float64(n))
	}
	return ans
}