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Add a ridiculously impractical 17 byte variant; edited body

edited Aug 11, 2016 at 19:10

40.7k
3
76
149

Pyth, 24 bytes

f&q4lJcT\.!-J`M256jL\../

Try it online

How it works

 ./Q all partitions of input jL\.  join each on . f  filter for results T such that: cT\.  split T on . J  assign to J l  length q4  equals 4 &  … and: -J`M256  J minus the list of representations of [0, …, 255] !  is false (empty)

Pyth, 17 bytes, very slow

@FjLL\.,^U256 4./

Warning. Do not run. Requires approximately 553 GiB of RAM.

How it works

 , two-element list of: ^U256 4 all four-element lists of [0, …, 255] ./Q all partitions of input jLL\. join each element of both on . @F fold intersection

Pyth, 24 bytes

f&q4lJcT\.!-J`M256jL\../

Try it online

How it works

 ./ all partitions of input jL\. join each on . f filter for results T such that: cT\. split T on . J assign to J l length q4 equals 4 & … and: -J`M256 J minus the list of representations of [0, …, 255] ! is false (empty)

Pyth, 24 bytes

f&q4lJcT\.!-J`M256jL\../

Try it online

How it works

 ./Q all partitions of input jL\.  join each on . f  filter for results T such that: cT\.  split T on . J  assign to J l  length q4  equals 4 &  … and: -J`M256  J minus the list of representations of [0, …, 255] !  is false (empty)

Pyth, 17 bytes, very slow

@FjLL\.,^U256 4./

Warning. Do not run. Requires approximately 553 GiB of RAM.

How it works

 , two-element list of: ^U256 4 all four-element lists of [0, …, 255] ./Q all partitions of input jLL\. join each element of both on . @F fold intersection

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answered Aug 11, 2016 at 18:53

Anders Kaseorg

40.7k
3
76
149

Pyth, 24 bytes

f&q4lJcT\.!-J`M256jL\../

Try it online

How it works

 ./ all partitions of input jL\. join each on . f filter for results T such that: cT\. split T on . J assign to J l length q4 equals 4 & … and: -J`M256 J minus the list of representations of [0, …, 255] ! is false (empty)