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Move-to-front algorithm: Difference between revisions
m
→version 2: added whitespace around DO loops.
m (→version 2: alternated types of literal strings, added whitespace.) |
m (→version 2: added whitespace around DO loops.) |
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Line 1,172:
do j=1 for words(stuff); x=word(stuff,j) /*process 1 word at a time*/
abc ='abcdefghijklmnopqrstuvwxyz'; $=
do k=1 for length(x); z=substr(x,k,1) /*encrypt a letter in word*/
_=pos(z,abc); if _==0 then iterate /*pos of letter in sym tab*/
$=$ _-1; abc=z || delstr(abc,_,1) /*adjust the symbol table.*/
end /*k*/ /* [↑] move-to-front alg.*/
abc= 'abcdefghijklmnopqrstuvwxyz'; != /*define the symbol table.*/
do m=1 for words($); n=word($,m)+1 /*decode the sequence tab.*/
y=substr(abc,n,1); !=! || y /*decode a letter of word.*/
abc=y || delstr(abc,n,1) /*re─build the symbol tab.*/
end /*m*/ /* [↑] show word, enc, OK*/
say 'word: ' left(x,20) "encoding:" left($,35) word('wrong OK',1+(!==x))
end /*j*/ /*done encoding/decoding words. */
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