feat: day2 part2 complete

1 files changed, 78 insertions, 0 deletions

diff --git a/day2/part2/main.ha b/day2/part2/main.ha
new file mode 100644
index 0000000..4778240
--- /dev/null
+++ b/day2/part2/main.ha
@@ -0,0 +1,78 @@
+use fmt;
+use io;
+use math::{ceilf64, log10f64};
+use os;
+use strconv;
+use strings::{cut, dup, freeall, fromutf8_unsafe, rtrim, split, sub};
+
+fn digits(num: u64) u8 = {
+	return ceilf64(log10f64(num: f64)): u8;
+};
+
+fn has_repeating_seq(num: u64) bool = {
+	let digits = digits(num);
+
+	if (digits == 1) return false;
+
+	let divisors: []u8 = [];
+	defer free(divisors);
+
+	let num_str = strconv::u64tos(num);
+
+	for (let i: u8 = 2; i <= digits; i += 1) {
+		if (digits % i == 0) {
+			let chunk_size = digits / i;
+			let first_chunk: str = "";
+			defer free(first_chunk);
+
+			let valid_seq = true;
+
+			for (let j: u8 = 0; j < i; j += 1) {
+				let chunk = dup(sub(num_str, chunk_size * j,
+					chunk_size * j + chunk_size))!;
+
+				if (j == 0) {
+					first_chunk = chunk;
+				} else {
+					if (chunk != first_chunk) {
+						valid_seq = false;
+						break;
+					};
+				};
+			};
+
+			if (valid_seq) return true;
+		};
+	};
+
+	return false;
+};
+
+export fn main() void = {
+	let handle = os::open("input.txt")!;
+	defer io::close(handle)!;
+
+	let buf = io::drain(handle) as []u8;
+	defer free(buf);
+
+	let range_strings = split(fromutf8_unsafe(buf), ",")!;
+	defer free(range_strings);
+
+	let answer: u64 = 0;
+
+	for (let i: size = 0; i < len(range_strings); i += 1) {
+		let range_ends = cut(rtrim(range_strings[i], '\n'), "-");
+
+		let start = strconv::stou64(range_ends.0)!;
+		let end = strconv::stou64(range_ends.1)!;
+
+		let start_digits = digits(start);
+		let end_digits = digits(end);
+
+		for (let num = start; num <= end; num += 1) {
+			if (has_repeating_seq(num)) answer += num;
+		};
+	};
+
+	fmt::printfln("Answer: {}", answer)!;
+};