Part 1: Create a 128x128 grid. Generate each row by taking the knot hash of
salt-{index}. The bits of the hash represent if a tile in the grid isfree(0) orused(1).
Given your salt as input, how many squares are
used?
Whenever I create my yearly reading list, I need a way to order the books. Sure, I could just shuffle them normally, but that leads me to the temptation of cheating and re-shuffling them so that the books I want to read most are first. What I really need is a shuffle that will shuffle the same way every time.
Enter: hashsort
Part 1: Starting with a list of the numbers from
1tonand a list oflengths(as input):
- Initialize
current_positionandskip_sizeto0- For each
lengthelement in thelengthslist:- Reverse the first
lengthelements of the list (starting atcurrent_position)- Move forward by
lengthplusskip_size- Increment
skip_sizeby 1
After applying the above algorithm, what is the product of the first two elements in the list (from the original first position, not the
current_position)?
Part 1: Create a 4x4 grid of rooms with doors
Up,Down,Left, andRight from each location. To determine if a door is currently open:
- Calculate
MD5(salt + sequence)where sequence is a string containing any combination ofUDLRdepending on how you got to this room- The first four hex values represent the doors
Up,Down,Left, andRight respectively:bcdefmeans open; anything else is closed
Find the shortest path from
(0, 0)to(3, 3).
Part 1: Calculate a series of MD5 hashes (the same as Day 5). A hash is considered valid if it contains a triple (three characters in a row) and somewhere in the next 1000 hashes there is a quintuple of that same character.
What index produces the 64th key?
Part 1: Generate a series of hashes: MD5(salt + index). For each hash starting with five zeros, write down the sixth character.
While I’ve been getting a fair few programming exercises from Reddit’s /r/dailyprogrammer, more recently I’ve started following a few other sub-Reddits, such as /r/programming and /r/netsec. While browsing the former, I came across this intriguing gem of a problem: HashChallenge: can you find the lowest value SHA-512 hash?