2023/go/day01/day01.go

   1 package day01
   2
   3 import (
   4         "adventofcode2023/utils"
   5          "fmt"
   6         "strings"
   7 )
   8 func Part1(input string) int {
   9         num := 0
  10         lines := strings.Split(input, "\n")
  11         for _, line := range lines {
  12                 for i:=0;i<len(line);i++ {
  13                         if line[i] >= '0' && line[i] <= '9' {
  14                                 num += utils.MustAtoi(string(line[i])) * 10
  15                                 break;
  16                         }
  17                 }
  18                 for i:=len(line) - 1;i>=0;i-- {
  19                         if line[i] >= '0' && line[i] <= '9' {
  20                                 num += utils.MustAtoi(string(line[i]))
  21                                 break;
  22                         }
  23                 }
  24         }
  25         return num
  26 }
  27
  28
  29 func Part2(input string) int {
  30         digits := make(map[string]string)
  31         digits["one"] = "1"
  32         digits["two"] = "2"
  33         digits["three"] = "3"
  34         digits["four"] = "4"
  35         digits["five"] = "5"
  36         digits["six"] = "6"
  37         digits["seven"] = "7"
  38         digits["eight"] = "8"
  39         digits["nine"] = "9"
  40
  41         digits_backwards := make(map[string]string)
  42         digits_backwards["eno"] = "1"
  43         digits_backwards["owt"] = "2"
  44         digits_backwards["eerht"] = "3"
  45         digits_backwards["ruof"] = "4"
  46         digits_backwards["evif"] = "5"
  47         digits_backwards["xis"] = "6"
  48         digits_backwards["neves"] = "7"
  49         digits_backwards["thgie"] = "8"
  50         digits_backwards["enin"] = "9"
  51
  52         num := 0
  53         found := false
  54         lines := strings.Split(input, "\n")
  55         for _, line := range lines {
  56                 for i:=0;i<len(line);i++ {
  57                         if line[i] >= '0' && line[i] <= '9' {
  58                                 fmt.Println("first digit:", string(line[i]))
  59                                 num += utils.MustAtoi(string(line[i])) * 10
  60                                 found = true
  61                         }
  62                         if found { break;}
  63                         for key := range digits {
  64                                 if strings.HasPrefix(line[i:], key) {
  65                                         fmt.Println("first digit:", digits[key])
  66                                         num += utils.MustAtoi(digits[key]) * 10
  67                                         found = true
  68                                 }
  69                                 if found { break;}
  70                         }
  71                 }
  72
  73                 found = false
  74
  75                 reverse := reverseString(line)
  76
  77                 for i:=0;i<len(reverse);i++ {
  78                         if reverse[i] >= '0' && reverse[i] <= '9' {
  79                                 fmt.Println("last digit:", string(reverse[i]))
  80                                 num += utils.MustAtoi(string(reverse[i]))
  81                                 found = true
  82                         }
  83                         if found { break;}
  84                         for key := range digits_backwards {
  85                                 if strings.HasPrefix(reverse[i:], key) {
  86                                         fmt.Println("last digit:", digits_backwards[key])
  87                                         num += utils.MustAtoi(digits_backwards[key])
  88                                         found = true
  89                                 }
  90                                 if found { break;}
  91                         }
  92                 }
  93                 found = false
  94
  95         }
  96         return num
  97 }
  98
  99 func reverseString(input string) string {
 100         // Convert the string to a rune slice
 101         runes := []rune(input)
 102
 103         // Get the length of the rune slice
 104         length := len(runes)
 105
 106         // Reverse the order of runes
 107         for i, j := 0, length-1; i < j; i, j = i+1, j-1 {
 108                 runes[i], runes[j] = runes[j], runes[i]
 109         }
 110
 111         // Convert the reversed rune slice back to a string
 112         reversedString := string(runes)
 113
 114         return reversedString
 115 }