Dice that hit a 5 or 6 can be re-rolled to doubled-down. Three dice are rolled. What's the the probability of getting 2 or more total points.

DiceProblem.swift

//: Playground - noun: a place where people can play

import Cocoa

/*
 Problem: There are three dice. 
 It counts as a point if any die hits a 5 or 6
 Any die that gets a 5 ot 6 is rolled again. If the second roll is 5 ot 6 that die has produced two points.
 */

struct Die {
    
    let value: Int = Die.roll()
    
    private static func roll() -> Int {
        
        var totalValue = 0
        let rollA = arc4random_uniform(6)
        
        if rollA == 4 || rollA == 5 {
            totalValue += 1
        } else {
            return 0
        }
        
        let rollB = arc4random_uniform(6)
        if rollB == 4 || rollB == 5 {
            totalValue += 1
        }
        return totalValue
    }
}


var counter = [0,0,0 ,0, 0,0,0]

( 0..<100_000 ).forEach { _ in
    let newDieTotalValue = Die().value + Die().value + Die().value
    counter[newDieTotalValue] = counter[newDieTotalValue] + 1
}

print(counter)