Advent of Code 2019 Day 2 - The Ugliness

day2.swift

import Cocoa

typealias IntcodeProgram = [Int]

func loadInput() throws -> IntcodeProgram {
    do {
        let inputFile = URL(fileReferenceLiteralResourceName: "input.txt")
        let rawInput = try String(contentsOf: inputFile)
        let splitFile = rawInput.components(separatedBy: .punctuationCharacters)
        return splitFile.compactMap { Int($0) }
    } catch {
        throw error
    }
}

var code = try! loadInput()
code[1] = 12
code[2] = 2

var idx = 0
func run(_ code: inout IntcodeProgram) {
    let opc = code[idx]
    let ebp = code[code[idx + 1]]
    let ebx = code[code[idx + 2]]
    let edi = code[idx + 3]
    
    switch opc {
    case 1:
        code[edi] = ebp + ebx
    case 2:
        code[edi] = ebp * ebx
    case 99:
        break
    default:
        return
    }
    idx += 4
}

while idx <= code.count - 5 {
    run(&code)
}

print(code.first!)