rolfschmidt, add 2024 day 11 (#72)

* Add 2024 day 11

* add output

* tidy

Author: rolfschmidt

2024/11/rolfschmidt.v

@@ -0,0 +1,48 @@
+import arrays
+import os
+
+fn halve_string(s string) []i64 {
+	half_len := s.len / 2
+	return [s[..half_len].i64(), s[half_len..].i64()]
+}
+
+fn run(rounds i64) i64 {
+	mut check := map[i64]i64{}
+
+	input := os.read_file('stones.input') or { '' }
+	for num in input.split(' ') {
+		check[num.i64()] = 1
+	}
+
+	for _ in 0 .. rounds {
+		mut cloned := map[i64]i64{}
+		for key, value in check {
+			cloned[key] = value
+		}
+
+		for num, count in cloned {
+			new_values := if num == 0 {
+				[i64(1)]
+			} else if num.str().len % 2 == 0 {
+				halve_string(num.str())
+			} else {
+				[num * i64(2024)]
+			}
+
+			check[num] -= count
+			for new_value in new_values {
+				if new_value !in check {
+					check[new_value] = 0
+				}
+				check[new_value] += count
+			}
+		}
+	}
+
+	return arrays.sum(check.values()) or { 0 }
+}
+
+fn main() {
+	println(run(25))
+	println(run(75))
+}

known/2024/11/rolfschmidt.out

@@ -0,0 +1,2 @@
+55312
+65601038650482