2023-day01.go

package main

import (
	"fmt"
	"log"
	"os"
	"strings"
	"time"
	"unicode"
)

func parseInput(test bool) []string {
	var data []byte
	if test {
		data = []byte(`two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen`)
	} else {
		b, err := os.ReadFile("input.txt")
		if err != nil {
			log.Println(err.Error())
			os.Exit(1)
		}
		data = b
	}

	return strings.Split(string(data), "\n")
}

func solve(in []string) (int, int) {
	letts := []string{"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"}

	sum1, sum2 := 0, 0

	for _, e := range in {
		digs1, digs2 := make([]int, 0, 4), make([]int, 0, 4)
		for i, c := range e {
			if unicode.IsDigit(c) {
				dig := int(c - '0')
				digs1 = append(digs1, dig)
				digs2 = append(digs2, dig)
			} else {
				for k, n := range letts {
					if strings.HasPrefix(e[i:], n) {
						digs2 = append(digs2, k)
						break
					}
				}
			}
		}

		if len(digs1) < 2 {
			digs1 = append(digs1, digs1[0])
		}
		if len(digs2) < 2 {
			digs2 = append(digs2, digs2[0])
		}

		num1 := 10 * digs1[0]
		num1 += digs1[len(digs1)-1]
		sum1 += num1

		num2 := 10 * digs2[0]
		num2 += digs2[len(digs2)-1]
		sum2 += num2

	}

	return sum1, sum2
}

func main() {
	start := time.Now()
	data := parseInput(false)
	solveStart := time.Now()
	p1, p2 := solve(data)
	solveTime := time.Since(solveStart)

	fmt.Printf("Part 1:\t%v\n", p1)
	fmt.Printf("Part 2:\t%v\n", p2)
	fmt.Printf("Solve Time:\t%s\n", solveTime)
	fmt.Printf("Run Time:\t%s\n", time.Since(start))
}