ijoshsmith

defmodule Money do

  @silver_dollar 100
  @half_dollar    50
  @quarter        25
  @dime           10
  @nickel          5
  @penny           1
  def all_coins, do: [@silver_dollar, @half_dollar, @quarter, @dime, @nickel, @penny]

ijoshsmith

# I wrote this after watching Dave Thomas review his implementation
# in this presentation: https://www.youtube.com/watch?v=5hDVftaPQwY
 
defmodule MyList do
 
  def encode(list), do: _encode(list, [])
  
  defp _encode([     a, a | tail], acc), do: _encode([  {a, 2} | tail], acc)
  defp _encode([{a, n}, a | tail], acc), do: _encode([{a, n+1} | tail], acc)
  defp _encode([{a, n}, b | tail], acc), do: _encode([       b | tail], [{a, n} | acc])

ijoshsmith

-- Zips together two lists in Haskell.
zip' :: [a] -> [b] -> [(a, b)]
zip' xs     []     = []
zip' []     ys     = []
zip' (x:xs) (y:ys) = (x, y) : zip' xs ys

-- Example usages:
-- zip' "ABCDE" [1,2,3]   …yields…  [('A',1),('B',2),('C',3)]
-- zip' "AB" [1,2,3,4,5]  …yields…  [('A',1),('B',2)]
-- zip' "ABC" []          …yields…  []

ijoshsmith

> foldr (-) 0 [3, 2, 1]
2
 
> (3 - (2 - (1 - 0)))
2
 
> foldl (-) 0 [3, 2, 1]
-6
 
> (((0 - 3) - 2) - 1)

ijoshsmith

import Foundation

/**
Returns a compacted array, with repeated values coalesced.
Example: [a, a, b, c, c, c] yields [(a, 2), (b, 1), (c, 3)]
*/
func compressArray<T: Comparable>(input: [T]) -> [(T, Int)] {
    // TODO - implement this function
    return []
}

ijoshsmith

//
//  main.swift
//  HigherOrderFunctions
//
//  Created by Joshua Smith on 12/6/15.
//  Copyright © 2015 iJoshSmith. All rights reserved.
//

/*
This file contains simple implementations of several 

ijoshsmith

extension Dictionary where Value: Equatable {
    /// Returns all keys mapped to the specified value.
    /// ```
    /// let dict = ["A": 1, "B": 2, "C": 3]
    /// let keys = dict.keysForValue(2)
    /// assert(keys == ["B"])
    /// assert(dict["B"] == 2)
    /// ```
    func keysForValue(value: Value) -> [Key] {
        return flatMap { (key: Key, val: Value) -> Key? in

ijoshsmith

  Dy MxT   MnT   AvT   HDDay  AvDP 1HrP TPcpn WxType PDir AvSp Dir MxS SkyC MxR MnR AvSLP

   1  88    59    74          53.8       0.00 F       280  9.6 270  17  1.6  93 23 1004.5
   2  79    63    71          46.5       0.00         330  8.7 340  23  3.3  70 28 1004.5
   3  77    55    66          39.6       0.00         350  5.0 350   9  2.8  59 24 1016.8
   4  77    59    68          51.1       0.00         110  9.1 130  12  8.6  62 40 1021.1
   5  90    66    78          68.3       0.00 TFH     220  8.3 260  12  6.9  84 55 1014.4
   6  81    61    71          63.7       0.00 RFH     030  6.2 030  13  9.7  93 60 1012.7
   7  73    57    65          53.0       0.00 RF      050  9.5 050  17  5.3  90 48 1021.8
   8  75    54    65          50.0       0.00 FH      160  4.2 150  10  2.6  93 41 1026.3

ijoshsmith

func findAnagramsIn(words: [String]) -> [[String]] {
    var signatureToAnagrams = [String: [String]]()
    for word in words {
        let signature = String(word.characters.sort())
        if let anagrams = signatureToAnagrams[signature] {
            signatureToAnagrams[signature] = anagrams + [word]
        }
        else {
            signatureToAnagrams[signature] = [word]
        }

ijoshsmith

/// Represents an entire Morse encoded message.
struct EncodedMessage { let encodedTerms: [EncodedTerm] }

/// Represents a word or number consisting of Morse code symbols.
struct EncodedTerm { let symbols: [Symbol] }

/// Represents a character encoded with Morse code marks.
struct Symbol { let marks: [Mark] }

/// Represents an individual component of a Morse code symbol.