add day6 solutions and tests

brute force approach won't work for part 2, needs updating to prevent
10+ gb of memory allocation

2021/06_test.odin

@@ -0,0 +1,57 @@
+package main
+
+import "core:fmt"
+import "core:testing"
+
+@(test)
+d06p1 :: proc(t: ^testing.T) {
+	input := "3,4,3,1,2"
+
+	want := 26
+	got := simulate_lanterfish_growth(input, 18)
+	testing.expect(t, got == want, fmt.tprintf("Got: %v | Want: %v", got, want))
+
+	want = 5934
+	got = simulate_lanterfish_growth(input, 80)
+	testing.expect(t, got == want, fmt.tprintf("Got: %v | Want: %v", got, want))
+
+	free_all()
+}
+
+//@(test)
+//d06p2 :: proc(t: ^testing.T) {
+//	input := "3,4,3,1,2"
+//
+//	want := 26984457539
+//	got := simulate_lanterfish_growth(input, 256)
+//	testing.expect(t, got == want, fmt.tprintf("Got: %v | Want: %v", got, want))
+//
+//	free_all()
+//}
+
+@(test)
+test_parse_laternfish :: proc(t: ^testing.T) {
+	input := "3,4,3,1,2"
+	want := [dynamic]int{3, 4, 3, 1, 2}
+	got := parse_lanterfish(input)
+
+	for fish, i in got {
+		testing.expect(t, fish == want[i], fmt.tprintf("Got: %v | Want: %v", fish, want[i]))
+	}
+
+	free_all()
+}
+
+@(test)
+test_simulate_laternfish_day :: proc(t: ^testing.T) {
+	fish := [dynamic]int{2, 3, 2, 0, 1}
+	want := [dynamic]int{1, 2, 1, 6, 0, 8}
+
+	simulate_lanternfish_day(&fish)
+
+	for i in 0 ..< len(fish) {
+		testing.expect(t, fish[i] == want[i], fmt.tprintf("Got: %v | Want: %v", fish[i], want[i]))
+	}
+
+	free_all()
+}

2021/06p1.odin

@@ -0,0 +1,46 @@
+package main
+
+import "core:fmt"
+import "core:strconv"
+import "core:strings"
+import "utils"
+
+D06P1 :: proc() {
+	lines, backing := utils.read_lines("./inputs/06.txt")
+	defer delete(lines)
+	defer delete(backing)
+
+	days := 80
+	total_lanterfish := simulate_lanterfish_growth(lines[0], days)
+	fmt.printfln("Number of lanterfish after %v days: %v", days, total_lanterfish)
+}
+
+simulate_lanterfish_growth :: proc(input: string, days: int) -> int {
+	fish := parse_lanterfish(input)
+	defer delete(fish)
+
+	for _ in 1 ..= days {
+		simulate_lanternfish_day(&fish)
+	}
+	return len(fish)
+}
+
+parse_lanterfish :: proc(input: string) -> (fish: [dynamic]int) {
+	fish_strs := strings.split(input, ",", context.temp_allocator)
+	for fish_str in fish_strs {
+		append(&fish, strconv.atoi(fish_str))
+	}
+	return
+}
+
+simulate_lanternfish_day :: proc(fish: ^[dynamic]int) {
+	for i in 0 ..< len(fish) {
+		switch fish[i] {
+		case 0:
+			fish[i] = 6
+			append(fish, 9) // append 9 instead of 8 because this fish will always be processed in this day
+		case:
+			fish[i] -= 1
+		}
+	}
+}

2021/06p2.odin

@@ -0,0 +1,14 @@
+package main
+
+import "core:fmt"
+import "utils"
+
+D06P2 :: proc() {
+	lines, backing := utils.read_lines("./inputs/06.txt")
+	defer delete(lines)
+	defer delete(backing)
+
+	days := 256
+	total_lanterfish := simulate_lanterfish_growth(lines[0], days)
+	fmt.printfln("Number of lanterfish after %v days: %v", days, total_lanterfish)
+}

2021/inputs/06.txt

@@ -0,0 +1 @@
+5,1,1,5,4,2,1,2,1,2,2,1,1,1,4,2,2,4,1,1,1,1,1,4,1,1,1,1,1,5,3,1,4,1,1,1,1,1,4,1,5,1,1,1,4,1,2,2,3,1,5,1,1,5,1,1,5,4,1,1,1,4,3,1,1,1,3,1,5,5,1,1,1,1,5,3,2,1,2,3,1,5,1,1,4,1,1,2,1,5,1,1,1,1,5,4,5,1,3,1,3,3,5,5,1,3,1,5,3,1,1,4,2,3,3,1,2,4,1,1,1,1,1,1,1,2,1,1,4,1,3,2,5,2,1,1,1,4,2,1,1,1,4,2,4,1,1,1,1,4,1,3,5,5,1,2,1,3,1,1,4,1,1,1,1,2,1,1,4,2,3,1,1,1,1,1,1,1,4,5,1,1,3,1,1,2,1,1,1,5,1,1,1,1,1,3,2,1,2,4,5,1,5,4,1,1,3,1,1,5,5,1,3,1,1,1,1,4,4,2,1,2,1,1,5,1,1,4,5,1,1,1,1,1,1,1,1,1,1,3,1,1,1,1,1,4,2,1,1,1,2,5,1,4,1,1,1,4,1,1,5,4,4,3,1,1,4,5,1,1,3,5,3,1,2,5,3,4,1,3,5,4,1,3,1,5,1,4,1,1,4,2,1,1,1,3,2,1,1,4

2021/main.odin

@@ -21,6 +21,8 @@ solutions: map[string]proc() = {
 	"04P2:Giant Squid"          = D04P2,
 	"05P1:Hydrothermal Venture" = D05P1,
 	"05P2:Hydrothermal Venture" = D05P2,
+	"06P1:Lanternfish"          = D06P1,
+	//"06P2:Lanternfish"          = D06P2,
 }
 
 main :: proc() {