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const std = @import("std");
const aoc = @import("aoc");
const Entry = struct { a: u16, b: u16, char: u8, pass: []u8 };
fn freeEntries(allocator: std.mem.Allocator, entries: *const std.ArrayList(Entry)) void {
for (entries.items) |item|
allocator.free(item.pass);
entries.deinit();
}
fn parse(allocator: std.mem.Allocator, input: []u8) !std.ArrayList(Entry) {
var entries = std.ArrayList(Entry).init(allocator);
errdefer freeEntries(allocator, &entries);
var lineit = std.mem.tokenize(u8, input, "\n");
while (lineit.next()) |line| {
var entry: Entry = undefined;
var it = std.mem.tokenize(u8, line, " -");
entry.a = try std.fmt.parseInt(u16, it.next().?, 10);
entry.b = try std.fmt.parseInt(u16, it.next().?, 10);
entry.char = it.next().?[0];
entry.pass = try allocator.dupe(u8, it.next().?);
try entries.append(entry);
}
return entries;
}
fn part1(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
const entries = try parse(allocator, input);
defer freeEntries(allocator, &entries);
var valid: u32 = 0;
for (entries.items) |entry| {
var count: u16 = 0;
for (entry.pass) |c| count += @boolToInt(c == entry.char);
valid += @boolToInt(count >= entry.a and count <= entry.b);
}
return try std.fmt.allocPrint(allocator, "{d}", .{valid});
}
fn part2(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
const entries = try parse(allocator, input);
defer freeEntries(allocator, &entries);
var valid: u32 = 0;
for (entries.items) |entry| {
valid += @boolToInt((entry.pass[entry.a - 1] == entry.char) !=
(entry.pass[entry.b - 1] == entry.char));
}
return try std.fmt.allocPrint(allocator, "{d}", .{valid});
}
pub const main = aoc.main(part1, part2, .{ "603", "404" });
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