Advent of Code 2023 Day 1 - Nim

part1.nim

import strutils, sequtils

var sum = 0

for line in lines "src/input.txt":
    let digits = line.filter isDigit
    sum += parseInt $digits[0] & $digits[^1]

echo sum

part1alternate.nim

import strutils

var sum = 0

for line in lines "src/input.txt":
    var digits = line
    for letter in line:
        if not isDigit letter:
            digits = digits.replace($letter, "")
    sum += parseInt $digits[0] & $digits[^1]

echo sum

part2.nim

import strutils, sequtils

func calibrated(line: string): string =
    let numbers = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
    result = line

    for i in 0..len line:
        for index, number in pairs numbers: 
            if number in line[0..<i]:
                result = result.replace(number[0..^2], $(index+1))  

var sum = 0

for line in lines "src/input.txt":
    var digits = (calibrated line).filter isDigit
    sum += parseInt $digits[0] & $digits[^1]

echo sum