mirror of
https://github.com/Threnklyn/advent-of-code-go.git
synced 2026-06-06 04:08:27 +02:00
2021 day22, took a while to figure out but just make a big list of on/off cubes
This commit is contained in:
alexchao26
@@ -0,0 +1,192 @@
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package main
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import (
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_ "embed"
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"flag"
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"fmt"
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"strings"
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"github.com/alexchao26/advent-of-code-go/mathy"
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"github.com/alexchao26/advent-of-code-go/util"
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)
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//go:embed input.txt
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var input string
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func init() {
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// do this in init (not main) so test file has same input
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input = strings.TrimRight(input, "\n")
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if len(input) == 0 {
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panic("empty input.txt file")
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}
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}
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func main() {
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var part int
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flag.IntVar(&part, "part", 1, "part 1 or 2")
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flag.Parse()
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fmt.Println("Running part", part)
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if part == 1 {
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ans := part1(input)
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util.CopyToClipboard(fmt.Sprintf("%v", ans))
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fmt.Println("Output:", ans)
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} else {
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ans := part2(input)
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util.CopyToClipboard(fmt.Sprintf("%v", ans))
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fmt.Println("Output:", ans)
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}
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}
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// naive brute force for part1
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func part1(input string) int {
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cubes := parseInput(input)
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onCoords := map[[3]int]bool{}
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for _, c := range cubes {
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if part1OutOfBounds(c.x1, c.x2, c.y1, c.y2, c.z1, c.z2) {
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continue
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}
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for x := c.x1; x <= c.x2; x++ {
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for y := c.y1; y <= c.y2; y++ {
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for z := c.z1; z <= c.z2; z++ {
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coord := [3]int{x, y, z}
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onCoords[coord] = c.isOn
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}
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}
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}
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}
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var count int
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for _, b := range onCoords {
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if b {
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count++
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}
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}
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return count
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}
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func part1OutOfBounds(nums ...int) bool {
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for _, n := range nums {
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if n < -50 || n > 50 {
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return true
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}
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}
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return false
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}
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func part2(input string) int {
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cubes := parseInput(input)
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var finalList []cube
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// iterate through all cubes, keep a final list of cubes
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// as new cubes are added, check against the entire final list and add any
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// intersections that are found
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for _, c := range cubes {
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// add these at the end of the step to prevent duplicate checks
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var toAdd []cube
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for _, finalCube := range finalList {
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intersection, didIntersect := finalCube.getIntersection(c)
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if didIntersect {
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toAdd = append(toAdd, intersection)
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}
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}
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// if cube is an "on" cube, it needs to be added to final list
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if c.isOn {
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toAdd = append(toAdd, c)
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}
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finalList = append(finalList, toAdd...)
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}
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var total int
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for _, c := range finalList {
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total += c.volume()
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}
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return total
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}
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type cube struct {
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isOn bool
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x1, x2 int
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y1, y2 int
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z1, z2 int
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}
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// NOTE: must be called in correct order (cube_from_final_list).getIntersection(cube_being_added)
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// because of how the isOn bool is determined
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func (c cube) getIntersection(c2 cube) (intersection cube, hasIntersection bool) {
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// larger of x1s has to be smaller than smaller of x2s for there to be an overlap
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x1 := mathy.MaxInt(c.x1, c2.x1)
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x2 := mathy.MinInt(c.x2, c2.x2)
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y1 := mathy.MaxInt(c.y1, c2.y1)
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y2 := mathy.MinInt(c.y2, c2.y2)
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z1 := mathy.MaxInt(c.z1, c2.z1)
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z2 := mathy.MinInt(c.z2, c2.z2)
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if x1 > x2 || y1 > y2 || z1 > z2 {
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return cube{}, false
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}
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var intersectionState bool
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if c.isOn && c2.isOn {
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intersectionState = false
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} else if !c.isOn && !c2.isOn {
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intersectionState = true
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} else {
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// ! default to second cube's on/off state. This makes the order of which cube's method is
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// called very important. but that's what unit tests are for :)
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// alternatively the caller could deal with it.. that might be more clear...
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intersectionState = c2.isOn
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}
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return cube{
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isOn: intersectionState,
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x1: x1, x2: x2,
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y1: y1, y2: y2,
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z1: z1, z2: z2,
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}, true
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}
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func (c cube) volume() int {
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vol := (c.x2 - c.x1 + 1) * (c.y2 - c.y1 + 1) * (c.z2 - c.z1 + 1)
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if c.isOn {
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return vol
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}
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return -vol
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}
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func parseInput(input string) (ans []cube) {
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for _, line := range strings.Split(input, "\n") {
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// off x=-29..-12,y=-13..5,z=-17..-3
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parts := strings.Split(line, " ")
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var x1, x2, y1, y2, z1, z2 int
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n, err := fmt.Sscanf(parts[1], "x=%d..%d,y=%d..%d,z=%d..%d", &x1, &x2, &y1, &y2, &z1, &z2)
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if err != nil || n != 6 {
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panic(fmt.Sprintf("parsing error %v, vals parsed %d", err, n))
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}
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if x1 > x2 || y1 > y2 || z1 > z2 {
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// note: they can be equal
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panic("didn't expect input to have backwards coords, sort them...")
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}
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ans = append(ans, cube{
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isOn: parts[0] == "on",
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x1: x1,
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x2: x2,
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y1: y1,
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y2: y2,
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z1: z1,
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z2: z2,
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})
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}
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return ans
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}
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@@ -0,0 +1,170 @@
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package main
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import (
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_ "embed"
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"testing"
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)
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var smallExample = `on x=10..12,y=10..12,z=10..12
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on x=11..13,y=11..13,z=11..13
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off x=9..11,y=9..11,z=9..11
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on x=10..10,y=10..10,z=10..10`
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var largeExample = `on x=-20..26,y=-36..17,z=-47..7
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on x=-20..33,y=-21..23,z=-26..28
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on x=-22..28,y=-29..23,z=-38..16
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on x=-46..7,y=-6..46,z=-50..-1
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on x=-49..1,y=-3..46,z=-24..28
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on x=2..47,y=-22..22,z=-23..27
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on x=-27..23,y=-28..26,z=-21..29
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on x=-39..5,y=-6..47,z=-3..44
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on x=-30..21,y=-8..43,z=-13..34
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on x=-22..26,y=-27..20,z=-29..19
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off x=-48..-32,y=26..41,z=-47..-37
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on x=-12..35,y=6..50,z=-50..-2
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off x=-48..-32,y=-32..-16,z=-15..-5
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on x=-18..26,y=-33..15,z=-7..46
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off x=-40..-22,y=-38..-28,z=23..41
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on x=-16..35,y=-41..10,z=-47..6
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off x=-32..-23,y=11..30,z=-14..3
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on x=-49..-5,y=-3..45,z=-29..18
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off x=18..30,y=-20..-8,z=-3..13
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on x=-41..9,y=-7..43,z=-33..15
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on x=-54112..-39298,y=-85059..-49293,z=-27449..7877
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on x=967..23432,y=45373..81175,z=27513..53682`
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func Test_part1(t *testing.T) {
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tests := []struct {
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name string
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input string
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want int
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}{
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{
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name: "smallExample",
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input: smallExample,
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want: 39,
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},
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{
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name: "largeExample",
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input: largeExample,
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want: 590784,
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},
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{
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name: "actual",
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input: input,
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want: 648681,
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := part1(tt.input); got != tt.want {
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t.Errorf("part1() = %v, want %v", got, tt.want)
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}
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})
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}
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}
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var part2Example = `on x=-5..47,y=-31..22,z=-19..33
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on x=-44..5,y=-27..21,z=-14..35
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on x=-49..-1,y=-11..42,z=-10..38
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on x=-20..34,y=-40..6,z=-44..1
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off x=26..39,y=40..50,z=-2..11
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on x=-41..5,y=-41..6,z=-36..8
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off x=-43..-33,y=-45..-28,z=7..25
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on x=-33..15,y=-32..19,z=-34..11
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off x=35..47,y=-46..-34,z=-11..5
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on x=-14..36,y=-6..44,z=-16..29
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on x=-57795..-6158,y=29564..72030,z=20435..90618
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on x=36731..105352,y=-21140..28532,z=16094..90401
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on x=30999..107136,y=-53464..15513,z=8553..71215
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on x=13528..83982,y=-99403..-27377,z=-24141..23996
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on x=-72682..-12347,y=18159..111354,z=7391..80950
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on x=-1060..80757,y=-65301..-20884,z=-103788..-16709
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on x=-83015..-9461,y=-72160..-8347,z=-81239..-26856
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on x=-52752..22273,y=-49450..9096,z=54442..119054
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on x=-29982..40483,y=-108474..-28371,z=-24328..38471
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on x=-4958..62750,y=40422..118853,z=-7672..65583
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on x=55694..108686,y=-43367..46958,z=-26781..48729
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on x=-98497..-18186,y=-63569..3412,z=1232..88485
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on x=-726..56291,y=-62629..13224,z=18033..85226
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on x=-110886..-34664,y=-81338..-8658,z=8914..63723
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on x=-55829..24974,y=-16897..54165,z=-121762..-28058
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on x=-65152..-11147,y=22489..91432,z=-58782..1780
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on x=-120100..-32970,y=-46592..27473,z=-11695..61039
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on x=-18631..37533,y=-124565..-50804,z=-35667..28308
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on x=-57817..18248,y=49321..117703,z=5745..55881
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on x=14781..98692,y=-1341..70827,z=15753..70151
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on x=-34419..55919,y=-19626..40991,z=39015..114138
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on x=-60785..11593,y=-56135..2999,z=-95368..-26915
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on x=-32178..58085,y=17647..101866,z=-91405..-8878
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on x=-53655..12091,y=50097..105568,z=-75335..-4862
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on x=-111166..-40997,y=-71714..2688,z=5609..50954
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on x=-16602..70118,y=-98693..-44401,z=5197..76897
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on x=16383..101554,y=4615..83635,z=-44907..18747
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off x=-95822..-15171,y=-19987..48940,z=10804..104439
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on x=-89813..-14614,y=16069..88491,z=-3297..45228
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on x=41075..99376,y=-20427..49978,z=-52012..13762
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on x=-21330..50085,y=-17944..62733,z=-112280..-30197
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on x=-16478..35915,y=36008..118594,z=-7885..47086
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off x=-98156..-27851,y=-49952..43171,z=-99005..-8456
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off x=2032..69770,y=-71013..4824,z=7471..94418
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on x=43670..120875,y=-42068..12382,z=-24787..38892
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off x=37514..111226,y=-45862..25743,z=-16714..54663
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off x=25699..97951,y=-30668..59918,z=-15349..69697
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off x=-44271..17935,y=-9516..60759,z=49131..112598
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on x=-61695..-5813,y=40978..94975,z=8655..80240
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off x=-101086..-9439,y=-7088..67543,z=33935..83858
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off x=18020..114017,y=-48931..32606,z=21474..89843
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off x=-77139..10506,y=-89994..-18797,z=-80..59318
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off x=8476..79288,y=-75520..11602,z=-96624..-24783
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on x=-47488..-1262,y=24338..100707,z=16292..72967
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off x=-84341..13987,y=2429..92914,z=-90671..-1318
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off x=-37810..49457,y=-71013..-7894,z=-105357..-13188
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off x=-27365..46395,y=31009..98017,z=15428..76570
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off x=-70369..-16548,y=22648..78696,z=-1892..86821
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on x=-53470..21291,y=-120233..-33476,z=-44150..38147
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off x=-93533..-4276,y=-16170..68771,z=-104985..-24507`
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func Test_part2(t *testing.T) {
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tests := []struct {
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name string
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input string
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want int
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}{
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{
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name: "part2Example",
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input: part2Example,
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want: 2758514936282235,
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},
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{
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name: "simple, no overlap",
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input: `on x=1..2,y=1..2,z=1..2
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on x=5..6,y=5..6,z=5..6`,
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want: 16,
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},
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{
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name: "simple, one overlap",
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input: `on x=1..3,y=1..3,z=1..3
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on x=2..4,y=2..4,z=2..4`,
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want: 46, // 27 + 27 - 8
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},
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{
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name: "simple, turn some off",
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input: `on x=1..3,y=1..3,z=1..3
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off x=2..4,y=2..4,z=2..4`,
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want: 19, // 27 - 8
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},
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{
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name: "actual",
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input: input,
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want: 1302784472088899,
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := part2(tt.input); got != tt.want {
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t.Errorf("part2() = %v, want %v", got, tt.want)
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}
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})
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}
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}
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Reference in New Issue
Block a user