题目：

题解：

func largestValues(root *TreeNode) (ans []int) {if root == nil {return}q := []*TreeNode{root}for len(q) > 0 {maxVal := math.MinInt32tmp := qq = nilfor _, node := range tmp {maxVal = max(maxVal, node.Val)if node.Left != nil {q = append(q, node.Left)}if node.Right != nil {q = append(q, node.Right)}}ans = append(ans, maxVal)}return
}func max(a, b int) int {if b > a {return b}return a
}