colmmacc

import sys

# choose() is the same as computing the number of combinations. Normally this is
# equal to:
#
#   factorial(N) / (factorial(m) * factorial(N - m))
#
# but this is very slow to run and requires a deep stack (without tail
# recursion).
#

colmmacc

How many ways can we express "::"

Both IPv4 and IPv6 allow for some flexibility in how IP addresses are expressed as strings, but IPv6 really takes it to the max. How many ways can we express the all-zeroes IPv6 address, a.k.a. "::". Let's see.

The obvious

 ::

Running count: 1.

colmmacc

extern crate sha2;
extern crate nix;
extern crate libc;

use sha2::{Sha256, Digest};
use nix::request_code_write;
use std::os::unix::prelude::*;
use std::os::raw::c_int;
use std::fs::File;
use std::mem;

colmmacc

Wordle Letter Frequency Table

If you're used to solving cryptic puzzles, or deciphering texts using crypt-analytical cribs, it can be useful to know the relative frequency of letters in the distribution of words. Wordle has a built-in list of 5-letter words. That list isn't the same as all of the five letter words in the dictionary, or even only the common ones. Perfectly common words like 'tudor' are omitted. This gist contains a few useful tables that are worth familiarizing yourself with if you want to solve wordle puzzles logically.

The raw frequency of each letter