2023/gareth/day06/day06.go

   1 package day06
   2
   3 type Race struct {
   4         Time     int
   5         Distance int
   6 }
   7
   8 func Part1(input string) int {
   9         var Races []Race
  10         Races = append(Races, Race{56, 546})
  11         Races = append(Races, Race{97, 1927})
  12         Races = append(Races, Race{78, 1131})
  13         Races = append(Races, Race{75, 1139})
  14
  15         total := 1
  16         for _, r := range Races {
  17                 halfTime := r.Time / 2
  18                 for i := 0; i <= halfTime; i++ {
  19                         raceDis := i * (r.Time - i)
  20                         if raceDis > r.Distance {
  21                                 total = total * (r.Time - (i * 2) + 1)
  22                                 break
  23                         }
  24                 }
  25         }
  26         return total
  27 }
  28
  29 func Part2(input string) int {
  30         r := Race{56977875, 546192711311139}
  31         halfTime := r.Time / 2
  32         for i := 0; i <= halfTime; i++ {
  33                 raceDis := i * (r.Time - i)
  34                 if raceDis > r.Distance {
  35                         return r.Time - (i * 2) + 1
  36
  37                 }
  38         }
  39         return -1
  40 }