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const std = @import("std");
pub fn puzzle_1(input: []const u8) u16 {
var iter = std.mem.split(u8, input, "\n");
var count: u16 = 0;
while (iter.next()) |line| {
var p1: u64 = 0;
var p2: u64 = 0;
for (line[0 .. line.len / 2]) |_, i| {
p1 |= @as(u64, 1) << @intCast(u6, line[i] - 65); // 65 == 'A'
p2 |= @as(u64, 1) << @intCast(u6, line[i + line.len / 2] - 65);
}
count += char_to_priority(@intCast(u8, 65 + 63) - @clz(p1 & p2));
}
return count;
}
pub fn puzzle_2(input: []const u8) u16 {
var iter = std.mem.split(u8, input, "\n");
var count: u16 = 0;
mainLoop: while (true) {
var parts = std.mem.zeroes([3]u64);
for (parts) |*p| {
const line = iter.next() orelse break :mainLoop;
for (line) |_, i| {
p.* |= @as(u64, 1) << @intCast(u6, line[i] - 65);
}
}
count += char_to_priority(@intCast(u8, 65 + 63) - @clz(parts[0] & parts[1] & parts[2]));
}
return count;
}
fn char_to_priority(char: u8) u8 {
if (char >= 65 and char <= 90)
return char - 38;
return char - 96;
}
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