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BSNode.swift
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BSNode.swift
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//
// BSNode.swift
// SwiftStructures
//
// Created by Wayne Bishop on 9/16/17.
// Copyright © 2017 Arbutus Software Inc. All rights reserved.
//
import Foundation
//generic node to be used with binary search trees (BST's)
class BSNode<T>{
var key: T?
var left: BSNode?
var right: BSNode?
var height: Int
init() {
self.height = -1
}
var count: Int {
let left = self.left?.count ?? 0
let right = self.right?.count ?? 0
return left + 1 + right
}
//regular dfs traversal
func traverse() {
//trivial condition
guard let key = self.key else {
print("no key provided..")
return
}
//process the left side
if self.left != nil {
left?.traverse()
}
print("...the value is: \(key) - height: \(self.height)..")
//process the right side
if self.right != nil {
right?.traverse()
}
}
//use dfs with trailing closure to update all values
func traverse(withFormula formula: (BSNode<T>) -> T) {
//check for trivial condition
guard self.key != nil else {
print("no key provided..")
return
}
//process the left side
if self.left != nil {
left?.traverse(withFormula: formula)
}
//invoke formula - apply results
let newKey: T = formula(self)
self.key! = newKey
print("...the updated value is: \(self.key!) - height: \(self.height)..")
//process the right side
if self.right != nil {
right?.traverse(withFormula: formula)
}
}
}