package q530

import "math"

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func getMinimumDifference(root *TreeNode) int {
	minDiff := math.MaxInt
	var last *int

	var check = func(num int) {
		if last == nil {
			last = &num
			return
		}
		minDiff = min(minDiff, num-*last)
		*last = num
	}
	var traverse func(node *TreeNode)
	traverse = func(node *TreeNode) {
		if node == nil {
			return
		}
		traverse(node.Left)
		check(node.Val)
		traverse(node.Right)
	}
	traverse(root)

	return minDiff
}

var _ = getMinimumDifference