junebash

// MARK: - Extensions

extension Task where Failure == Never {
  public var cancellableValue: Success {
    get async {
      await withTaskCancellationHandler {
        await self.value
      } onCancel: {
        self.cancel()
      }

junebash

actor TaskQueue {
    private var queuedOperations: [() async -> Void] = [] // should probably be an actual `Queue`/`Deque` type
    private var currentTask: Task<Void, Never>?
    private var iterationTask: Task<Void, Never>?

    init() {}

    func addOperation(_ operation: @escaping () async -> Void) {
        if currentTask == nil {
            currentTask = Task {

junebash

import Foundation

/// Prints the week in Markdown format. Useful for planning. Throw this into a TextExpander shell script!
func markdownWeek() -> String {
  let cal = Calendar.current

  func weekDay(of date: Date) -> Int {
    cal.component(.weekday, from: date)
  }

junebash

struct CodeChallengeTestCases<Input, Output> {
   var title: String?
   var expected: KeyValuePairs<Input, Output>
   var solution: (Input) -> Output

   init(
      title: String? = nil,
      expected: KeyValuePairs<Input, Output> = [:],
      solution: @escaping (Input) -> Output)
   {

junebash

func commonChars(_ inputs: [String]) -> [String] {
    guard let lastString = inputs.last else { return [] }

    var commonCountedChars = CountedSet<String>()
    for char in lastString {
        commonCountedChars.add(String(char))
    }
    var strings = inputs
    strings.removeLast()
    // removing last is more computationally efficient than removing first in Swift

junebash

func reverseOnlyLetters(_ inputString: String) -> String {
    let lettersReversed = [Character](
        inputString.compactMap { char -> Character? in
            return char.isLetter ? char : nil
        }.reversed()
    )

    var outputCharacters = [Character](inputString)
    var i = 0
    while i < lettersReversed.count {

junebash

/*
Given a matrix A, return the transpose of A.
The transpose of a matrix is the matrix flipped over it's main diagonal,
switching the row and column indices of the matrix.
 
Example 1:
Input: [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]
 
Example 2:

junebash

func findMissingNumbers(_ nums: [Int]) -> [Int] {
    var includedNums = [Int:Int]()
    var missingNums = [Int]()
    
    for num in nums {
        includedNums[num] = num
    }
    
    for i in 1...nums.count {
        if includedNums[i] == nil {

junebash

func indicesToSum(from array: [Int], to target: Int) -> [Int] {
    for i in 1 ..< array.count {
        for j in 0 ..< i {
            if array[i] + array[j] == target { return [j,i] }
        }
    }
    print("ERROR: No sum possible!")
    return []
}

junebash

//
//  CGExtensions.swift
//
//  Created by Jon Bash on 2019-11-06.
//  Copyright © 2019 Jon Bash. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
//   of this software and associated documentation files (the "Software"), to
//   deal in the Software without restriction, including without limitation the
//   rights to use, copy, modify, merge, publish, distribute, sublicense, and/or