132 lines
2.6 KiB
Go
Executable File
132 lines
2.6 KiB
Go
Executable File
package main
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import (
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"fmt"
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"sort"
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"strings"
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h "git.bullercodeworks.com/brian/adventofcode/helpers"
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)
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func main() {
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fmt.Println("# Day 13")
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inp := h.StdinToStringSlice()
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if len(inp) != 2 {
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fmt.Println("Invalid input")
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return
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}
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part1(inp)
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part2Rework(inp)
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}
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func part1(inp []string) {
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me := h.Atoi(inp[0])
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pts := strings.Split(inp[1], ",")
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earliest := h.MAX_INT
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var earliestBus int
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for k := range pts {
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if pts[k] == "x" {
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continue
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}
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bus := h.Atoi(pts[k])
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div := me / bus
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wait := (bus * (div + 1)) - me
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if earliest > wait {
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earliest = wait
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earliestBus = bus
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}
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}
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fmt.Println("## Part 1")
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fmt.Printf("Answer %d\n\n", earliest*earliestBus)
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}
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// This may not work with all inputs...
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func part2Rework(inp []string) {
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pts := strings.Split(inp[1], ",")
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buses := make(map[int]int)
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var keys []int
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for k, v := range pts {
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if v == "x" {
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continue
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}
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keys = append(keys, k)
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buses[k] = h.Atoi(v)
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}
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for _, v := range buses {
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if !h.IsPrime(v) {
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fmt.Println("Not all buses are prime numbers... This solution _may not work_. Or it may still.", h.SHRUG)
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break
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}
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}
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res := 0
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mins := buses[keys[0]]
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for k := 1; k < len(keys); k++ {
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wrk := keys[k]
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bus := buses[wrk]
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for (res+wrk)%bus != 0 {
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res = res + mins
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}
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mins = mins * bus
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}
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fmt.Println("## Part 2")
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fmt.Printf("Answer: %d\n", res)
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}
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/*
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7 13 59 31 19
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1068781 D . . . .
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1068782 . D . . .
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1068783 . . . . .
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1068784 . . . . .
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1068785 . . D . .
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1068786 . . . . .
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1068787 . . . D .
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1068788 D . . . D
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7 = 0
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13 = 1
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59 = 4
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31 = 6
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19 = 7
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*/
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// I think this will get there... Eventually... Maybe...
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func part2(inp []string) {
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pts := strings.Split(inp[1], ",")
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wrk := make(map[int]int)
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var keys []int
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var vals []int
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var highK, highV int
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for k := range pts {
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if pts[k] == "x" {
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continue
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}
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keys = append(keys, k)
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vals = append(vals, wrk[k])
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wrk[k] = h.Atoi(pts[k])
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if wrk[k] > highV {
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highK = k
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highV = wrk[k]
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}
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}
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sort.Sort(sort.Reverse(sort.IntSlice(keys)))
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sort.Sort(sort.Reverse(sort.IntSlice(keys)))
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target := highV - highK
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for !checkMap(target, keys, wrk) {
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target = target + highV
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}
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fmt.Println("## Part 2")
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fmt.Printf("Answer: %d\n", target)
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}
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func checkMap(target int, keys []int, all map[int]int) bool {
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for _, k := range keys {
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if (target+k)%all[k] != 0 {
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return false
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}
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}
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return true
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}
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