package q450

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

func del(node *TreeNode) *TreeNode {
	if node == nil || node.Left == nil && node.Right == nil {
		return nil // is leaf
	}
	if node.Left == nil {
		return node.Right
	}
	if node.Right == nil {
		return node.Left
	}

	p := node.Left
	for p.Right != nil {
		p = p.Right
	}
	p.Right = node.Right
	return node.Left
}

func findAndDel(node **TreeNode, key int) {
	if *node == nil {
		return
	}
	if (**node).Val == key {
		*node = del(*node)
	} else if key < (**node).Val {
		findAndDel(&(**node).Left, key)
	} else {
		findAndDel(&(**node).Right, key)
	}
}

func deleteNode(root *TreeNode, key int) *TreeNode {
	findAndDel(&root, key)
	return root
}

var _ = deleteNode