Solution.go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func longestConsecutive(root *TreeNode) (ans int) {
	var dfs func(*TreeNode) int
	dfs = func(root *TreeNode) int {
		if root == nil {
			return 0
		}
		l := dfs(root.Left) + 1
		r := dfs(root.Right) + 1
		if root.Left != nil && root.Left.Val-root.Val != 1 {
			l = 1
		}
		if root.Right != nil && root.Right.Val-root.Val != 1 {
			r = 1
		}
		t := max(l, r)
		ans = max(ans, t)
		return t
	}
	dfs(root)
	return
}