const std = @import("std");

pub fn main() void {
    const input = @embedFile("input.asc");

    std.debug.print("Part 1: {}\n", .{findDisctinctSubstrIdx(input, 4)});
    std.debug.print("Part 2: {}\n", .{findDisctinctSubstrIdx(input, 14)});
}

fn findDisctinctSubstrIdx(input: []const u8, n: usize) usize {
    // Loop through all the groups of 4
    var i: usize = n;
    group: while (i < input.len) : (i += 1) {
        const slice = input[(i - n)..i];

        // See if each one of them is unique in smaller groups.
        // Ex.: is 1 in 234? -> is 2 in 34? -> is 3 in 4?
        var j: usize = 0;
        while (j < slice.len - 1) : (j += 1) {
            const needle = slice[j];
            const haystack = slice[(j + 1)..];

            for (haystack) |blade| {
                // We found a match, throw batch to garbage

                if (needle == blade) {
                    // We know this character appears somewhere else in
                    // the haystack. As long as this letter is here, this
                    // n-letter work will be invalid. Skip ahead.
                    i += j;
                    continue :group;
                }
            }
        }

        // We found it, get out
        break;
    }

    return i;
}