How do you convert a stream of digits in one base into a stream of digits in another base?
Written up on my blog at http://checkmyworking.com/2012/06/converting-a-stream-of-binary-digits-to-a-stream-of-base-n-digits/
Christian Lawson-Perfect christianp
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| digraph{ | |
| overlap=false; | |
| splines=true; | |
| "d0" [label="0"]; | |
| "d1" [label="1"]; | |
| "d2" [label="2"]; | |
| "d4" [label="4"]; | |
| "d16" [label="16"]; | |
| "d37" [label="37"]; | |
| "d58" [label="58"]; |
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| SCORM Engine Log | |
| Version not.official.release.15337 keyboard shortcuts: refresh "r", close "esc" | |
| Displaying: Control Runtime Sequencing Sequencing P-Code Look-ahead P-Code Refresh All | |
| Refresh With Filter Expand All | |
| Collapse All Send to Support | |
| Save Debug Log | |
christianp
/ gist:2891557
Created
June 7, 2012 21:14
Using random walks on regular expressions to generate passwords
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| Regular expressions are equivalent to finite state automata. (well, lookahead needs a pushdown automaton, but that's OK) | |
| Describe password constraints using regular expressions. | |
| Randomly traverse the FSA corresponding to a password constraint. A path ending in an accepting state is a valid password. |
christianp
/ alphabat.py
Created
June 10, 2012 21:35
Trying to find the reordering of the alphabet containing the most (contiguous) English words
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| import sys | |
| import pickle | |
| import operator | |
| import itertools | |
| alphabet = 'abcdefghijklmnopqrstuvwxyz' | |
| #test if a word uses letters at most once | |
| def monoglyphic(word): | |
| word = sorted(word) |
christianp
/ README.md
Created
June 11, 2012 19:00
convert a stream of uniform random binary digits into a stream of uniform random base-n digits
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| https://cloud.scorm.com/ScormEngineInterface/PENS.jsp?command=collect&pens-version=1.0.0&package-type=scorm-pif&package-type-version=1.3&package-format=zip&package-id=http%3A//tallaght.ncl.ac.uk/exam/1/mas1041_20122013_cba1/&package-url=http%3A//tallaght.ncl.ac.uk/exam/1/mas1041_20122013_cba1.zip%3Fscorm&package-url-expiry=2013-05-20T1T16%3A05%3A39Z&client=Christian%20Perfect&receipt=mailto%3Achristianperfect@gmail.com&alerts=mailto%3Achristianperfect@gmail.com&system-user-id=<<<app ID from SCORM Cloud>>>&system-password=<<<secret key from SCORM Cloud>>> |
christianp
/ go.bat
Created
July 17, 2012 21:55
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| @echo off | |
| IF %1==north cd .. | |
| IF not %1==north cd %* |
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| define({a:1}); |
christianp
/ update-editor.sh
Created
July 25, 2012 16:06
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| #!/bin/sh | |
| EDITOR_PATH=/srv/www/numbas.mas.ncl.ac.uk80/numbas/ | |
| PYTHON=python2.6 | |
| echo "Updating Numbas" | |
| cd /srv/numbas/dist | |
| git pull | |
| echo "Updating editor" | |
| cd $EDITOR_PATH | |
| git pull | |
| $PYTHON manage.py syncdb |
A card trick based on a de Bruijn sequence
Encode cards as 6-digit binary strings. Arrange them following a de Bruijn sequence. Get someone to draw 6 cards, and tell you their colours. You can tell them exactly which cards they have.
Written up on The Aperiodical at http://aperiodical.com/2012/08/davids-de-bruijn-sequence-card-trick/