Author:

• Name: Taketo Konno
  Location: JP - Japan

To build:

    make

There is an unobfuscated version of this entry. See Alternate code below.

To use:

    ./konno N

Try:

    ./try.sh

    # you can also specify numbers to try before the random and preselected ones:
    ./try.sh 111 222 333 444 555 666 777 888 999

Try running try.sh a number of times as the first part randomly selects ten numbers to try.

Alternate code:

An alternate version of this entry, konno.alt.c, is provided. This alternate code is an unobfuscated version of the winning code.

Alternate build:

    make alt

Alternate use:

Use konno.alt as you would konno above.

Judges’ remarks:

This entry is a good one-liner to analyze completely.

For extra credit, what are the minimal changes to convert it to 64-bit integers so that it could print 32 lines?

Author’s remarks:

Remarks

This program outputs elementary cellular automaton patterns.

Try:

    ./konno 30
    ./konno 90
    ./konno 102
    ./konno 109
    ./konno 165

There are 256 (from 0 through 255) possible rules.

Obfuscation

This program uses bit operations. I think

    7&O<<!o>>!o+29

is an interesting operation. This isn’t equal to

    7&O>>29

operation. What is the operation doing?

Limitation

This program assumes that the size of int is 4.

Primary files

• konno.c - entry source code
• Makefile - entry Makefile
• konno.alt.c - alternate source code
• konno.orig.c - original source code
• try.sh - script to try entry

Secondary files

• 2012_konno.tar.bz2 - download entry tarball
• README.md - markdown source for this web page
• .entry.json - entry summary and manifest in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top level directory
• index.html - this web page

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