adventofcode/2023/day01/main.go

package main

import (
	"fmt"

	h "git.bullercodeworks.com/brian/adventofcode/helpers"
)

func main() {
	inp := h.StdinToStringSlice()
	part1(inp)
	part2(inp)
}

func part1(input []string) {
	var value int
	for _, i := range input {
		value = value + getValue(i, false)
	}
	fmt.Println("# Part 1")
	fmt.Println(value)
}

var nums = []string{
	"zero",
	"one",
	"two",
	"three",
	"four",
	"five",
	"six",
	"seven",
	"eight",
	"nine",
}

func part2(input []string) {
	var value int
	for _, i := range input {
		value = value + getValue(i, true)
	}
	fmt.Println("# Part 2")
	fmt.Println(value)
}

func getValue(wrk string, p2 bool) int {
	return (getFirstValue(wrk, p2) * 10) + getLastValue(wrk, p2)
}
func getFirstValue(wrk string, p2 bool) int {
	for j := 0; j < len(wrk); j++ {
		if p2 {
			v := numStringAt(wrk, j)
			if v > -1 {
				return v
			}
		}
		if wrk[j]-'0' >= 0 && wrk[j]-'0' <= 9 {
			return int(wrk[j] - '0')
		}
	}
	return 0
}
func getLastValue(wrk string, p2 bool) int {
	for j := len(wrk) - 1; j >= 0; j-- {
		if p2 {
			v := numStringAt(wrk, j)
			if v > -1 {
				return v
			}
		}
		if wrk[j]-'0' >= 0 && wrk[j]-'0' <= 9 {
			return int(wrk[j] - '0')
		}
	}
	return 0
}

func numStringAt(haystack string, pos int) int {
	for i := range nums {
		if stringAt(haystack, pos, nums[i]) {
			return i
		}
	}
	return -1
}

func stringAt(haystack string, pos int, needle string) bool {
	if len(haystack) < pos+len(needle) {
		return false
	}
	for i := range needle {
		if haystack[pos+i] != needle[i] {
			return false
		}
	}
	return true
}