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
  30 func Part2(input string) int {
  31         digits := make(map[string]string)
  32         digits["one"] = "1"
  33         digits["two"] = "2"
  34         digits["three"] = "3"
  35         digits["four"] = "4"
  36         digits["five"] = "5"
  37         digits["six"] = "6"
  38         digits["seven"] = "7"
  39         digits["eight"] = "8"
  40         digits["nine"] = "9"
  41
  42         digits_backwards := make(map[string]string)
  43         digits_backwards["eno"] = "1"
  44         digits_backwards["owt"] = "2"
  45         digits_backwards["eerht"] = "3"
  46         digits_backwards["ruof"] = "4"
  47         digits_backwards["evif"] = "5"
  48         digits_backwards["xis"] = "6"
  49         digits_backwards["neves"] = "7"
  50         digits_backwards["thgie"] = "8"
  51         digits_backwards["enin"] = "9"
  52
  53         num := 0
  54         found := false
  55         lines := strings.Split(input, "\n")
  56         for _, line := range lines {
  57                 for i:=0;i<len(line);i++ {
  58                         if line[i] >= '0' && line[i] <= '9' {
  59                                 fmt.Println("first digit:", string(line[i]))
  60                                 num += utils.MustAtoi(string(line[i])) * 10
  61                                 found = true
  62                         }
  63                         if found { break;}
  64                         for key := range digits {
  65                                 if strings.HasPrefix(line[i:], key) {
  66                                         fmt.Println("first digit:", digits[key])
  67                                         num += utils.MustAtoi(digits[key]) * 10
  68                                         found = true
  69                                 }
  70                                 if found { break;}
  71                         }
  72                 }
  73
  74                 found = false
  75
  76                 reverse := reverseString(line)
  77
  78                 for i:=0;i<len(reverse);i++ {
  79                         if reverse[i] >= '0' && reverse[i] <= '9' {
  80                                 fmt.Println("last digit:", string(reverse[i]))
  81                                 num += utils.MustAtoi(string(reverse[i]))
  82                                 found = true
  83                         }
  84                         if found { break;}
  85                         for key := range digits_backwards {
  86                                 if strings.HasPrefix(reverse[i:], key) {
  87                                         fmt.Println("last digit:", digits_backwards[key])
  88                                         num += utils.MustAtoi(digits_backwards[key])
  89                                         found = true
  90                                 }
  91                                 if found { break;}
  92                         }
  93                 }
  94                 found = false
  95
  96         }
  97         return num
  98 }
  99
 100 func reverseString(input string) string {
 101         // Convert the string to a rune slice
 102         runes := []rune(input)
 103
 104         // Get the length of the rune slice
 105         length := len(runes)
 106
 107         // Reverse the order of runes
 108         for i, j := 0, length-1; i < j; i, j = i+1, j-1 {
 109                 runes[i], runes[j] = runes[j], runes[i]
 110         }
 111
 112         // Convert the reversed rune slice back to a string
 113         reversedString := string(runes)
 114
 115         return reversedString
 116 }