SPOILER-SPOILER-Advent-Of-Code-4.swift

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

import Cocoa

let source = """
...
"""

func hasDuplicates(_ line: String) -> Bool {
    return line.components(separatedBy: " ")
        .reduce(into: [String: Int](), { result, word in
            if let count = result[word] {
                result[word] = count + 1
            } else {
                result[word] = 1
            }
        })
        .reduce(false, { result, group in
            return result || group.value > 1
        })
}

hasDuplicates("aa bb cc dd ee")
hasDuplicates("aa bb cc dd aa")
hasDuplicates("aa bb cc dd aaa")

func letters(from word: String) -> [Character] {
    var result = [Character]()
    for letter in word {
        result.append(letter)
    }
    
    return result
}

func containsAnagrams(_ line: String) -> Bool {
    let allLetters = line.components(separatedBy: " ")
        .map(letters)
        .map { String($0.sorted()) }
    
    let uniqueSize = Set<String>(allLetters).count
    let originalSize = allLetters.count
    
    return uniqueSize != originalSize
}

containsAnagrams("abcde fghij")                 // valid -> false
containsAnagrams("abcde xyz ecdab")             // invalid -> true
containsAnagrams("a ab abc abd abf abj")        // valid -> false
containsAnagrams("iiii oiii ooii oooi oooo")    // valid -> false
containsAnagrams("oiii ioii iioi iiio")         // invalid -> true

enum Result {
    case valid
    case hasDuplicates
    case hasAnagrams
}

func isValid(_ line: String) -> Result {
    guard !hasDuplicates(line) else { return .hasDuplicates }
    
    guard !containsAnagrams(line) else { return .hasAnagrams }
    
    return .valid
}

isValid("abcde fghij")                 // valid
isValid("abcde xyz ecdab")             // invalid
isValid("a ab abc abd abf abj")        // valid
isValid("iiii oiii ooii oooi oooo")    // valid
isValid("oiii ioii iioi iiio")         // invalid


source
    .components(separatedBy: "\n")
    .map(isValid)
    .filter { $0 == .valid }
    .count