merge gaming pc solutions

2024/2/odin/example.txt

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9

2024/2/odin/main.odin

@@ -0,0 +1,87 @@
+package aoc2024day2
+
+import "core:fmt"
+import "core:math"
+import "core:os"
+import "core:strconv"
+import "core:strings"
+
+EXAMPLE_INPUT_PATH :: "example.txt"
+PUZZLE_INPUT_PATH :: "input.txt"
+
+main :: proc() {
+	path := len(os.args) == 2 ? os.args[1] : EXAMPLE_INPUT_PATH
+	data := os.read_entire_file(path) or_else panic(fmt.tprintf("failed to read", path))
+	defer delete(data)
+
+	numbers: [dynamic]int
+	defer delete(numbers)
+
+	counter1 := 0
+	counter2 := 0
+
+	it := string(data)
+	for line in strings.split_lines_iterator(&it) {
+		for word in strings.split(line, " ") {
+			number := strconv.parse_int(word) or_else panic(fmt.tprintf("failed to parse", word))
+			append(&numbers, number)
+		}
+
+		diffs := diff(&numbers)
+		counter1 += int(safe(&diffs))
+
+		// or-reduction on safe of each tolerated diff
+		b := false
+		for &combination in tolerate(&numbers) {
+			diffs := diff(&combination)
+			if safe(&diffs) {
+				b = true
+				break
+			}
+		}
+		counter2 += int(b)
+
+		clear(&numbers)
+	}
+
+	fmt.println("part 1: there were", counter1, "safe reports.")
+	fmt.println("part 2: there were", counter2, "safe reports.")
+}
+
+diff :: proc(nums: ^[dynamic]int) -> [dynamic]int {
+	out: [dynamic]int
+	for cur, i in nums {
+		if len(nums) - 1 == i {break}
+		next := nums[i + 1]
+		append(&out, next - cur)
+	}
+	return out
+}
+
+safe :: proc(diffs: ^[dynamic]int) -> bool {
+	for cur, i in diffs {
+		// not on last element of list ? ... : default
+		next := len(diffs) - 1 != i ? diffs[i + 1] : cur
+		// not (same sign and greater than zero && at most 3)
+		if !(cur * next > 0 && cur * cur <= 9) {
+			return false
+		}
+	}
+	// fmt.println(safe ? "safe" : "unsafe")
+	return true
+}
+
+tolerate :: proc(diffs: ^[dynamic]int) -> [dynamic][dynamic]int {
+	out: [dynamic][dynamic]int
+	for d, i in diffs {
+		new: [dynamic]int
+		append(&out, new)
+	}
+	for d, i in diffs {
+		start: []int = diffs^[0:i]
+		end: []int = diffs^[i + 1:len(diffs)]
+		append(&out[i], ..start)
+		append(&out[i], ..end)
+	}
+	return out
+}