Binary Search Tree -- example

Binary-Search-Tree-AddNode.playground

import UIKit


class NodeTree<T: Comparable> {
    
    var key: T?
    var leftNode:NodeTree?
    var rightNode: NodeTree?
    
    init(key:T, leftChild: NodeTree?, rightChild: NodeTree?) {
        self.key = key
        self.leftNode = leftChild
        self.rightNode = rightChild
    }
    
    
    init() {
        
    }
    
    func addNode(key: T) {
        
        //check if head node
        if(self.key == nil) {
            self.key = key
            return
        }
        
        //chekc if left side of the tree
        if (key < self.key!) {
            if(self.leftNode != nil) {
                leftNode!.addNode(key:key)
            } else {
                let leftChild:NodeTree = NodeTree()
                leftChild.key = key
                self.leftNode = leftChild
            }
        }
        
        //check the right side of the tree
        if (key > self.key!) {
            
            if(self.rightNode != nil) {
                rightNode!.addNode(key: key)
            } else {
                let rightChild:NodeTree = NodeTree()
                rightChild.key = key
                self.rightNode = rightChild
            }
            
        }
    
    } //end of function addNode
    
}


//a simple array of unsorted integers
let numberList : Array<Int> = [8, 2, 10, 9, 11, 1, 7]

//create a new BST instance
var root = NodeTree<Int>()

//sort each item in the list
for number in numberList {
    root.addNode(key:number)
}

print("root:", root)

Simple Example of Binary Search Tree --- coding test for iOS