fine.hin

1984-1993模糊 C 源代码竞赛.zip 非常的好,不过这是DOS格式,要用UE去打开.

Best One Liner: <[e-mail]> Thomas A. Fine

	Thomas A. Fine
	Ohio State University
	Department of Computer and Information Science
	2036 Neil Avenue Mall
	Columbus, Ohio  43210
	USA


Judges' comments:

    Make and run as follows:

	make fine
	echo "green terra
	vex
	tang
	vend onyx
	cheryl be flashy
	rail
	clerk" | fine

    This filter, 80 chars plus a newline, fits into a single line on most 
    terminals (unless your terminal has a line wrap mis-feature :-)).

    This entry is likely one of the smallest C implementations of this
    filter, excluding programs that resort to command line or include 
    file tricks.

    How does this program work?  Which 3 bytes of C code can be changed
    into 2 bytes, allowing the program to still work, but also stripping 
    the high bit off of some input?


Selected notes from the author:

    The author wishes to thank J Greely for the last 6 bytes.

    Here's about how it does it:  [rot13 to read]

    
    ABGR:  Ovgf ner ersreerq gb nf 76543210, uvtu gb ybj.
    
    1.  Trg gur punenpgre va inevnoyr n.  Abgr gur sha jnl jr purpx sbe RBS.
        (gunaxf W).
    
    2.  Erirefr ovg 6, naq fgevc ovg 5.  Ovg 6 qrgrezvarf (zbfgyl) jurgure
        be abg guvf punenpgre vf n yrggre.  Ovg 5 jbhyq qrgrezvar pnfr vs
        jr pnerq.  Nffvta guvf inyhr gb inevnoyr o (Jr arrq gb fnir vg,
        fvapr jr arrq gb znxr 2 pbzcnevfbaf naq znlor bar bcrengvba jvgu
        guvf inyhr).  Jr pna'g nohfr bhe svefg inevnoyr, fvapr vg fnirf gur
        ovgf jr'er punatvat.
    
    3.  Purpx guvf inyhr gb frr vs vg vf n yrggre.  Vg zhfg or aba-mreb -
        vs vg vf mreb, gura jr unir rvgure gur ng-fvta (64) be gur
        onpxdhbgr (96).  Vg nyfb zhfg or yrff guna 27 - guvf purpxf gur
        enatr sbe yrggref nf jryy nf vzcyvpvgyl purpxvat gur inyhr bs ovg 6
        (vs vg jnf bevtvanyyl pyrne, vg vf frg abj, fb o jbhyq or gb ovt).
    
    4.  Vs vg vf abg n yrggre, gur pbaqvgvbany rkcerffvba vafvqr bs gur
        chgpune() ergheaf gur bevtvany punenpgre (n).  Bgurejvfr, vg
        ergheaf n ernyyl zrffl rkcerffvba gung cresbezf gur npghny ebgngvba
        naq svkrf gur svsgu naq fvkgu ovgf:
    
        N.  Fhogenpg 1, gb trg vagb gur enatr 0-25 (sbe gur zbqhyb bcrengvba).
        O.  Nqq 13 gb gur punenpgre.  Fgrcf N naq O ner pbzovarq.
        P.  Gnxr guvf zbqhyb 26 gb znxr gur nqqvgvba jenc nebhaq.
        Q.  Svk ovgf 5 naq 6, onfrq ba inevnoyr n.
        R.  Nqq 1 onpx va (jr gbbx vg bhg va fgrc N.)  Guvf vf bxnl gb qb
    	*nsgre* fgrc Q, orpnhfr jr xabj gur nqqvgvba jba'g gevpxyr hc
    	cnfg gur sbhegu ovg (o jbhyq unir gb or 31 sbe guvf gb unccra).
    
    Abgvpr gung guvf vzcyrzragngvba bcrengrf bayl ba punenpgref jvgu gur
    uvtu ovg pyrne.  Gur uvtu ovg pna or vtaberq jvgubhg punatvat gur fvmr
    bs gur cebtenz.  Nyfb, vs lbh xabj lbh ner bayl qrnyvat jvgu frira ovg
    qngn, gur fvmr pna or erqhprq ol bar olgr.  Gurfr ner yrsg nf rkrepvfrf
    sbe gur fghqrag.