basInput$ = "1113222113"
pred$ = ""
act$ = ""
new$ = ""
nb = 0

maxx=peek("screenwidth")-1:maxy=peek("screenheight")-1
clear screen

for i = 0 to 40
    print i, " / 40"
    for j = 1 to len(basInput$) step nb
        print at(0,i) i," / 40 mots | ",j," / ",len(basInput$)," lettres"
        act$ = mid$(basInput$, j, 1)
        if (act$ = mid$(basInput$, j + 1, 1)) then
            if (act$ = mid$(basInput$, j + 2, 1)) then
                nb = 3
            else
                nb = 2
            endif
        else
            nb = 1
        endif
        new$ = new$ + str$(nb) + act$
        next j
    basInput$ = new$
    next i

rem ancien code
rem print new$
rem for i = 0 to 40
rem     print i, " / 40"
rem     for j = 1 to len(basInput$) step k
rem         k = 1
rem         act$ = mid$(basInput$, j, 1)
rem         pred$ = act$
rem         while pred$ = act$ and (j + k) < len(basInput$)
rem             pred$ = act$
rem             act$ = mid$(basInput$, j + k, 1)
rem             k = k + 1
rem             if act$ <> pred$ then
rem                 k = k - 1
rem             endif
rem         wend
rem         new$ = new$ + str$(k) + pred$
rem         next j
rem     basInput$ = new$
rem     next i

print "La longeur de la chaine finale est ", len(basInput$)