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Day 14

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Sven Weidauer 2021-12-14 22:33:06 +01:00
parent e5f2ac72bd
commit cd1ab56170
1 changed files with 151 additions and 0 deletions
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@main
struct Day14 {
mutating func run() {
let part1 = calculate(start, depth: 10)
print("Part 1:", part1.values.max()! - part1.values.min()!)
let part2 = calculate(start, depth: 40)
print("Part 2:", part2.values.max()! - part2.values.min()!)
}
mutating func calculate(_ string: String, depth: Int) -> [Character: Int] {
var result: [Character: Int] = [:]
for (a, b) in zip(string, string.dropFirst()) {
result.merge(calculate(a, b, depth: depth), uniquingKeysWith: +)
}
result[string.last!, default: 0] += 1
return result
}
struct CacheKey: Hashable {
var string: String
var depth: Int
}
var cache: [CacheKey: [Character: Int]] = [:]
mutating func calculate(_ first: Character, _ second: Character, depth: Int) -> [Character: Int] {
guard depth > 0 else {
return [first: 1]
}
let pair = "\(first)\(second)"
let cacheKey = CacheKey(string: pair, depth: depth)
if let result = cache[cacheKey] {
return result
}
let mid = mapping[pair]!
var result = calculate(first, mid, depth: depth - 1)
result.merge(calculate(mid, second, depth: depth - 1), uniquingKeysWith: +)
cache[cacheKey] = result
return result
}
let start = "KBKPHKHHNBCVCHPSPNHF"
let mapping: [String: Character] = [
"OP": "H",
"CF": "C",
"BB": "V",
"KH": "O",
"CV": "S",
"FV": "O",
"FS": "K",
"KO": "C",
"PP": "S",
"SH": "K",
"FH": "O",
"NF": "H",
"PN": "P",
"BO": "H",
"OK": "K",
"PO": "P",
"SF": "K",
"BF": "P",
"HH": "S",
"KP": "H",
"HB": "N",
"NP": "V",
"KK": "P",
"PF": "P",
"BK": "V",
"OF": "H",
"FO": "S",
"VC": "P",
"FK": "B",
"NK": "S",
"CB": "B",
"PV": "C",
"CO": "N",
"BN": "C",
"HV": "H",
"OC": "N",
"NB": "O",
"CS": "S",
"HK": "C",
"VS": "F",
"BH": "C",
"PC": "S",
"KC": "O",
"VO": "P",
"FB": "K",
"BV": "V",
"VN": "N",
"ON": "F",
"VH": "H",
"CN": "O",
"HO": "O",
"SV": "O",
"SS": "H",
"KF": "N",
"SP": "C",
"NS": "V",
"SO": "F",
"BC": "P",
"HC": "C",
"FP": "H",
"OH": "S",
"OB": "S",
"HF": "V",
"SC": "B",
"SN": "N",
"VK": "C",
"NC": "V",
"VV": "S",
"SK": "K",
"PK": "K",
"PS": "N",
"KB": "S",
"KS": "C",
"NN": "C",
"OO": "C",
"BS": "B",
"NV": "H",
"FF": "P",
"FC": "N",
"OS": "H",
"KN": "N",
"VP": "B",
"PH": "N",
"NH": "S",
"OV": "O",
"FN": "V",
"CP": "B",
"NO": "V",
"CK": "C",
"VF": "B",
"HS": "B",
"KV": "K",
"VB": "H",
"SB": "S",
"BP": "S",
"CC": "F",
"HP": "B",
"PB": "P",
"HN": "P",
"CH": "O",
]
}