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Category Archives: Math

I love math, but I didn’t know that while I was learning it. Better late than never !

Attaque mathématique des codes Bixi (vélo libre-service)

J’étais au centre ville aujourd’hui et j’avais affaire pas très loin. Au lieu d’utiliser le métro, j’ai loué un Bixi, vélo en libre service. J’ai été surpris de constater que les codes Bixi ne comporte que 3 chiffres, sur 5 caractères, soit 3^5=243 codes possibles. Ça semble bien peu, mais si les codes ne sont […]

Easy test coverage with constant Hamming distance of 1

I left a terrible bug in version 1.3 of my replacement Gina. I didn’t want to miss any test case this time, so I wrote a batch file that tests every one of them. That batch file adds a user to a group and a group to the registry. There are two possible groups in […]

Counting on your 1024 fingers

Last week I went to a conference given by Mathieu Hébert. He was showing off, and somewhat teaching, his ability to do mathematical operations on his fingers (article in French), using each one as a binary digit. Ten fingers makes for 1024 combinaisons, allowing to represent number as big as 1023 since it starts with […]