Advent of Code 2023 - Day 1 (Part A)

day-1.ts

type NumberArr = { '0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9 }

type Count<A, S extends 0[] = []> = A extends S['length'] ? S : Count<A, [...S, 0]>
type Add<A, B> = [...Count<A>, ...Count<B>]['length']

type ParseInt<T extends string> 
  = T extends `${infer N extends number}` ? N : never;

type Combine<A extends number, B extends number> = 
    ParseInt<`${A}${B}`>

type Sum<Arr extends number[], Total extends number = 0> = Arr extends [infer First, infer Second, ...infer Rest]
    ? Rest extends number[]
        ? First extends number
            ? Second extends number
                ? Sum<Rest, Add<Total, Add<First, Second> extends infer S ? S extends number ? S : 0 : 0> extends infer T extends number ? T : 0>
                : Total
            : Total
        : Total
    : Total

type Trim<Str extends string> = Str extends `${infer First} ${infer Rest}`
    ? First extends ''
        ? Trim<Rest>
        : Rest
        : Str

type SplitTrim<Str extends string, Char extends string, Acc extends string[] = []> = 
    Str extends `${infer C}${Char}${infer Rest}`
        ? SplitTrim<Rest, Char, Trim<C> extends '' ? Acc : [...Acc, Trim<C>]>
        : Acc

type GetNumbersFromString<Arr extends string, Acc extends any[] = []> =
    Arr extends `${infer First}${infer Rest}`
        ? First extends keyof NumberArr
            ? GetNumbersFromString<Rest, [...Acc, NumberArr[First]]>
            : GetNumbersFromString<Rest, Acc>
        : Acc

type GetFirstAndLastArr<Arr extends any[]> = [
    Arr[0], 
    Arr extends [infer _, ...infer Rest] ? Arr[Rest['length']] : 0
]

type TotalPerLine<Lines extends string[], TotalArr extends number[] = []> =
    Lines extends [infer First, ...infer Rest]
        ? First extends string
            ? Rest extends string[]
                ? GetFirstAndLastArr<GetNumbersFromString<First>> extends [infer AFirst, infer ALast]
                    ? AFirst extends number
                        ? ALast extends number
                            ? TotalPerLine<Rest, [...TotalArr, Combine<AFirst, ALast>]>
                            : TotalArr
                        : TotalArr
                    : TotalArr
                : TotalArr
            : TotalArr
        : TotalArr

type Test = `
    1abc2
    pqr3stu8vwx
    a1b2c3d4e5f
    treb7uchet
`

type Result = Sum<TotalPerLine<SplitTrim<Test, '\n'>>>
//      ^?