Most frequent k chars distance: Difference between revisions

=={{header|J}}==

'''Solution''':<lang j>NB. String Distance Wrapper Function

mfksDF =: {:@:[ - (mfks@:(mfkh&.>)~ {.)~

NB. Most Frequent K Distance

mfks =: score@:(charMap@:[ {"1 charVals@:])/@:kHashes

score =. ([ +/ .* =)/ NB. (+ +/ .* *.&:*)/ for sum += freq_in_left + freq_in_right

charMap =. (,&< i.&> <@:~.@:,)&;/

charVals =. (; , 0:)"1

kHashes =. 0 1 |: ({.&>~ [: <./ #&>)

NB. Most Frequent K Hashing

mfkh =: _&$: : (takeK freqHash) NB. Default LHA of _ means "return complete frequency table"

takeK =. (<.#) {. ]

freqHash =. ~. (] \:~ ,.&:(<"0)) #/.~

NB. No need to fix mfksDF

mfkh =: mfkh f.

mfks =: mfks f.</lang>

'''Examples''':<lang j>verb define ''

fkh =. ;@:,@:(":&.>) NB. format k hash

assert. 'r2e2 e2s1' (-: [: fkh 2&mfkh)&>&;: 'research seeking'

assert. 2 = mfks 2 mfkh&.> 'research';'seeking'

assert. 'n1i1 n1a1' (-: [: fkh 2&mfkh)&>&;: 'night nacht'

assert. 9 = 2 10 mfksDF 'night';'nacht'

assert. 'm1y1 a1' (-: [: fkh 2&mfkh)&>&;: 'my a'

assert. 10 = 2 10 mfksDF 'my';'a'

assert. 'r2e2' -: fkh 2 mfkh 'research'

assert. 6 = 2 10 mfksDF 'research';'research' NB. task says 8; right answer is 6

assert. 'a5b4 a5b4' (-: [: fkh 2&mfkh)&>&;: 'aaaaabbbb ababababa'

assert. 1 = 2 10 mfksDF 'aaaaabbbb';'ababababa'

assert. 'i3n2 i3a2' (-: [: fkh 2&mfkh)&>&;: 'significant capabilities'

assert. 7 = 2 10 mfksDF 'significant';'capabilities' NB. task says 5; right answer is 7

assert. 'L9T8 F9L8' (-: [: fkh 2&mfkh)&>&;: 'LCLYTHIGRNIYYGSYLYSETWNTGIMLLLITMATAFMGYVLPWGQMSFWGATVITNLFSAIPYIGTNLV EWIWGGFSVDKATLNRFFAFHFILPFTMVALAGVHLTFLHETGSNNPLGLTSDSDKIPFHPYYTIKDFLG'

assert. 100 = 2 100 mfksDF 'LCLYTHIGRNIYYGSYLYSETWNTGIMLLLITMATAFMGYVLPWGQMSFWGATVITNLFSAIPYIGTNLV';'EWIWGGFSVDKATLNRFFAFHFILPFTMVALAGVHLTFLHETGSNNPLGLTSDSDKIPFHPYYTIKDFLG'

NB. task says 83; right answer is 100

'pass'

)

pass</lang>

'''Notes''': As of press time, there are significant discrepancies between the task description, its pseudocode, the test cases provided, and the two other existing implementations. See the [[Talk:Most frequent k chars distance#Prank_Page.3F|talk page]] for the assumptions made in this implementation to reconcile these discrepancies (in particular, in the scoring function).