Best use of weasel words

イタチの言葉の最高の使い方

Line wrap

Highlight

    #include<stdio.h>
    #include<stdlib.h>
    #include<string.h>
    #include<ctype.h>
    #include<time.h>
    #include<stdint.h>
    Q unsigned d; Q char E; Q int k;
    Q long u; Q size_t t; Q const char U;
    #define L toupper
    #define M SIZE_MAX-1
    #ifndef S
    #define S 38
    #elif S < 38
    #undef S
    #define S 38
    #elif S > M
    #undef S
    #define S M
    #endif
    #define l S-1
    #define Y strlen
    #define Z printf
    #define K static
    #define z do{
    K E W[]="stqvvwxzwtzuvvryusuxvtrqsruxttrxvwqxq"; K E T[S]= {77,69,84,72,73,78,75,83,32,73,84,32,73,83,32,76,73,75,69,32,65,32,87,69,65,83,69,76,0} ;
    K U C[] =" !\"#$<%:>&'()*+,-./0123456789;=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`{|}~";
    /*NO*/
    K E P[2][sizeof(T)]; K t G=0;
    #ifndef N
    #define N 25
    #elif N < 4
    #undef N
    #define N 3
    #elif N > M
    #undef N
    #define N M
    #endif
    /*BLOB*/
    K u R=1; K d D=0; K k X(k f,k t){ return (rand()%((t)-(f)+1)+(f)); }
    K E c() {return C[X(0,(k)Y(C)-1)];%> Q struct x { E G[sizeof T];
    t F; } x; K x O[N];
    /* Special C main() handler (encapsulation): */
    #define r(main) main
    r(k main(k a, E **V)) { x x; E*b;
    U *A=T; k h=0,s,q=0,m=0,y=0,n=N==97,J=0; t i,j,

    /* prototype for special C parser H() below */
    F H(); H(<% H(for (s = 1; s < a && *V[s++]; ) H(<%
    H(E *v=V[s-1]; H(if (*v!='-'||h) H(g(o) w(f) H(
    while (*++v) H(switch (*v) { w(case '-') h=1; g(f)
    w(case 'r') H(if ((R=strtol(v+1,&b,0)) < 1 || R > 100)/*CODING*/
    <% Z("mutation rate out of range\n") ; m=1); %> else m=0; g(f)
    w(case 'q') q=1; Z("quiet output\n") ; g(f) w(case 'm') J=1;
    g(f) w(default) g(f) %>); H(continue))); H(w(o) H(y=1; 
    H(i = Y(V<:s-1]); H(if(i > l) i=l; H( strncpy(T,V[s-1:>,i)
    ; H(T[i]='\0')))))))); })); }); H(H(if (n&&!y) for (j=0
    ; j<37; ++j) T[j]=W[j]-'A'); H(for ( ; *A && strchr(C, L(*A))
    ; ++A)); H(if (*A) <% Z("'%c' not in keyboard \"%s\"\n", *A,C)
    ; return 1; })/*THIS*/); H(srand((d)time(0)); memset(&x, 0, sizeof x);
    memset(O,0,sizeof O)); H(Z(/*IS*/"target '%s'\n", T); H(Z(
    "mutation rate %ld\n", R)); H(if((m=(m||J||N<4)))
    Z("monkey at typewriter\n"); H(for ( j=0; j<N; ++j) H(for
    (i=0; i<Y(T); ++i) O[j].G[i]=c())))); H(while (!D) { H(if (++

    G==M) {Z("Too many attempts, blaming the monkey Eric even if "
    "he isn't typing or doesn't exist. Bye.\n"); return 1; } H(for
    (j=0; j<N&&!D; ++j) { F = 0;/*NOT*/ H(for (i =0; i < Y(T); ++i)) { H(
    if (L(O[j].G[i]) == L(T[i]))) ++F; } /*A*/ O[j].F=F; H(if (((D=(F==Y(T)))
    ||G==1)&&(!q||D)) Z("Generation %4zu\tOffspring %2zu: %s\n",G
    -1,j+1,O[j] .G); })); H(if (D)break;); s=0; /*COMPACT*/ H(if (m) g(p) else H(z
    s=1; H(for(i=0; i<N-1; ++i) { H(if (O<:i].F >= O[i+1].F) g(h)) x=O[
    i+1:>; O[i]=O[i+1]; O[i+1]=x; s=0; w(h); }); }while(!s))); w(p
    ) H(strcpy(P[0],O[0].G); strcpy(P[1],O[1].G)); H(for (j=0; j<N; ++j)
    { H(for (i=0;!m&&i<Y(T); ++i) H(if ( X(0,9)<5) O[j] .
    G[i]=P[0][i]); H(else O[j] .  G[i]=P[1][i];)); /*BLOB*/ H(if (!
    q) Z("Generation %4zu\tOffspring %2zu: %s -> " ,G,j+1,O[j].
    G); H(for/*OF*/ (i=0; i<Y(T); ++i) { H(if (X(1,100) <= R || m)
    O[j].G[i]=c(); })); H(if (!q) Z("%s (%s)\n",O[j].G,m
    ?"monkey typing" : "mutation"))); /*OCTETS*/ }); H(if (!
    q) Z("**\n")); })); return 0; }

引用元：https://www.ioccc.org/2018/ferguson/prog.c

審査員・作者による説明：https://www.ioccc.org/2018/ferguson/hint.html

動作

イタチプログラムのプログラム。

“METHINKS IT IS LIKE A WEASEL”という文字列になるまで突然変異を繰り返す。

$ gcc -DQ='typedef' -D'g(o)'='goto o;' -D'w(x)'="x:" -D'H(main)'='r(main)' -o prog prog.c

$ ./prog
target 'METHINKS IT IS LIKE A WEASEL'
mutation rate 1
Generation    0 Offspring  1: |N03B7!?D0]*^#{8|SGYV;FA*V[|
Generation    0 Offspring  2:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X
Generation    0 Offspring  3: `[5C7:#G2^Z]VF DS](}QV([8),
Generation    0 Offspring  4: 3-XY%(4A[7K(1@LM",U5:`481B.O
Generation    0 Offspring  5: /$0(1% 7Z_=0]<=T>M9R\)%}P;6~
Generation    0 Offspring  6: BK/4/E%F+N`#H|3@"5,R ,@@}F=N
Generation    0 Offspring  7: F8.KI%}[K$9YR_@]\6{A1S,]|/5{
Generation    0 Offspring  8: X6*{T!G5:>VRT*'$P*|'FA,[,!S*
Generation    0 Offspring  9: 0NQN"AJWC)R*]DCL1MQ~Z.R}R{9{
Generation    0 Offspring 10: |'Q-8 ^=B%XHZEURL07{CNC`_X_,
Generation    0 Offspring 11: T3S1$#:?# @>N0PD9$.#_+G=\N66
Generation    0 Offspring 12: A[H.U_>9|-=HX_QB*~!)K/-FA7G`
Generation    0 Offspring 13: #C2E7@6R|A&_Q'%E$7"Z{K!H]YQ{
Generation    0 Offspring 14: ,0]ZVU|S-3#+8TP:_6,}SY80? =`
Generation    0 Offspring 15: Y'\K 4AV:=>55S&SC9;;V-}:L|7:
Generation    0 Offspring 16: |X"6|A EY$_`<"[ 5~3[9T[*G;1+
Generation    0 Offspring 17: 7/]_<_0K~0(X_<SHOJH#)_AH.`5X
Generation    0 Offspring 18: 5-I2BB,'~B5}6D6[)>=?2"BADFMU
Generation    0 Offspring 19: AH(9X4Q]YC#9I8||B48/"ZQ4?V8F
Generation    0 Offspring 20: 4K^9,$XJ}>C8K&W,:TTJ%(?PH("J
Generation    0 Offspring 21: D!(=,$Z=P.LN6'$G0=W|VF'?1I(\
Generation    0 Offspring 22: 4UA[VL2I0R"}F.-_8\B.3\,:;6F2
Generation    0 Offspring 23: FQ)]B.4[@,?T{<2C3E 2;<&3{5 |
Generation    0 Offspring 24: 2F/[[=3`OM6S\9B9AWB7`B/`H9.:
Generation    0 Offspring 25: T.$L73BX593"$PU{:Z5(-ZES_XN<
Generation    1 Offspring  1:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  2:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  3:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  4:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  5:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  6:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  7:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  8:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring  9:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 10:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 11:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 12:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 13:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT{*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 14:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 15:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 16:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 17:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 18:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 19:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 20:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 21:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 22:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 23:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 24:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    1 Offspring 25:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"'[X (mutation)
**
Generation    2 Offspring  1:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  2:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  3:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  4:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJC6"';X (mutation)
Generation    2 Offspring  5:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  6:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  7:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  8:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring  9:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 10:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 11:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 12:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[O|]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 13:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 14:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*G6!6"';X (mutation)
Generation    2 Offspring 15:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 16:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 17:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 18:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 19:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(62LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 20:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 21:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 22:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*#[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 23:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 24:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
Generation    2 Offspring 25:  DT|*K[OH]Q:(J2LMY"*GJ!6"';X ->  DT|*K[OH]Q:(J2LMY"*GJ!6"';X (mutation)
**
...
**
Generation 1099 Offspring  1: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  2: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  3: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  4: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  5: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  6: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  7: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  8: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring  9: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LYK: A WEASEL (mutation)
Generation 1099 Offspring 10: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 11: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 12: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 13: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 14: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 15: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WE]SEL (mutation)
Generation 1099 Offspring 16: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 17: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 18: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 19: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 20: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 21: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 22: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 23: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 24: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1099 Offspring 25: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
**
Generation 1100 Offspring  1: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  2: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  3: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  4: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  5: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  6: METHINKS IT IS LIK: A WEASEL -> METHINKS IT ISSLIK: A WEASEL (mutation)
Generation 1100 Offspring  7: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  8: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring  9: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 10: METHINKS IT IS LIK: A WEASEL -> METHINKS I) IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 11: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 12: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEUSEL (mutation)
Generation 1100 Offspring 13: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 14: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 15: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS :IK: A WEASEL (mutation)
Generation 1100 Offspring 16: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIKE A WEASEL (mutation)
Generation 1100 Offspring 17: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 18: METHINKS IT IS LIK: A WEASEL -> METJINKS IT IS LUK: A WEASEL (mutation)
Generation 1100 Offspring 19: METHINKS IT IS LIK: A WEASEL -> METHINLS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 20: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 21: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 22: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 23: METHINKS IT IS LIK: A WEASEL -> YETHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 24: METHINKS IT IS LIK: A WEASEL -> METHINKS IT IS LIK: A WEASEL (mutation)
Generation 1100 Offspring 25: METHINKS IT IS LIK: A WEASEL -> METH>NKS IT IS LIK: A WEASEL (mutation)
**
Generation 1100 Offspring 16: METHINKS IT IS LIKE A WEASEL

ターゲットの文字列は指定できる。

$ ./prog "Hello, world!"
target 'Hello, world!'
mutation rate 1
Generation    0 Offspring  1: &Q>S^24)TN41
Generation    0 Offspring  2: <VB:|W29/0|H"
Generation    0 Offspring  3: 9:UY!_EQ-=!G*
Generation    0 Offspring  4: 5-:,XT 2\}PT|
Generation    0 Offspring  5: E"_&$4XYS;30&
...
Generation 1159 Offspring 21: HELLOM WORLD! -> HELLOM WORLD! (mutation)
Generation 1159 Offspring 22: HELLOM WORLD! -> HELLOM WORLD! (mutation)
Generation 1159 Offspring 23: HELLOM WORLD! -> HELLOM WORLD! (mutation)
Generation 1159 Offspring 24: HELLOM WORLD! -> HELLOM WORLD! (mutation)
Generation 1159 Offspring 25: HELLOM WORLD! -> HELLOM WORLD! (mutation)
**
Generation 1159 Offspring 15: HELLO, WORLD!

-mオプションを渡すと、完全ランダム探索になる。

./prog -m
target 'METHINKS IT IS LIKE A WEASEL'
mutation rate 1
monkey at typewriter
Generation    0 Offspring  1: NLS{Y1RM)9URM\CN=1PPG2- C, }
Generation    0 Offspring  2: E:4V3N2R|"7Q"R!O):5K8#^}`&}?
Generation    0 Offspring  3: `F;#M5YFI'0&)-;VE=@Q>X_:=8M|
Generation    0 Offspring  4: :+9#T9%~4CE`-8L~K$V(<.?+M7]%
Generation    0 Offspring  5: UE#@S"C<")${/)]BG:<UT[`YO7J4
Generation    0 Offspring  6: 4B!PJ$(5O. Q;$MPX>U|XZRG0-}}
Generation    0 Offspring  7: +I2>N3X\}FWM7X{X?)%0]=-P1FZG
Generation    0 Offspring  8: VX>~~=>.4C>2M_E"R$;U.%#QE[~9
Generation    0 Offspring  9: ~YFVLO5,>#@"'H`WB@9X>ZH{C+M#
Generation    0 Offspring 10: LL?L#! O05^}~{ QD`%J~B :_(K=
Generation    0 Offspring 11: 60$HBD,E>,W8(16R-{=5]D|?!|&D
Generation    0 Offspring 12: PT|$"!L:>?,X.!+92'Q&O'AGN!I0
Generation    0 Offspring 13: FR7.A_]%`:ULF~?X .W^}D"MN%W`
Generation    0 Offspring 14: :8V-P(A)M6ZH@JWJIZ;*%,%L3P2
Generation    0 Offspring 15: 6:C#%\0VJTF/P};S)-5U<5ES(+7A
Generation    0 Offspring 16: ^O$Z7']#!(9KB|@*D^DP&\#VXID}
Generation    0 Offspring 17: W^"1)O&&Y")=*(LP&>@-!~`R?}%/
Generation    0 Offspring 18: 'JX|%;YZ:|FD~2|UAI#*Q%;2%`J>
Generation    0 Offspring 19: ^P|L]5)~U 9@|}~E0D]4PCD I{2/
Generation    0 Offspring 20: \C|6+_H:/TNK4<N1KM9BT\Y?|6?G
Generation    0 Offspring 21: ]595[71$\\SR+95E<!9P.9* 0J"Y
Generation    0 Offspring 22: FB8=Z76PTM4,:%{]B1;G];[QYKQO
Generation    0 Offspring 23: -SCVXAXM\)`+;0;:66 =- I>;?9.
Generation    0 Offspring 24: <>D3?"OZ:BC}O!):1*V-FVOWW0B,
Generation    0 Offspring 25: 2B$7J(0L*}B\@HZ'IJYAWKQ`~}2V
Generation    1 Offspring  1: NLS{Y1RM)9URM\CN=1PPG2- C, } -> 8&-<7(WY@&}?_(02&FE4{0>0..*} (monkey typing)
Generation    1 Offspring  2: E:4V3N2R|"7Q"R!O):5K8#^}`&}? -> /GNW^3G{39BJ/>S&XPS?=-I: 569 (monkey typing)
Generation    1 Offspring  3: `F;#M5YFI'0&)-;VE=@Q>X_:=8M| ->  M+AL<ZI@[JFL/"+6C,(T.`?ZJ!W (monkey typing)
Generation    1 Offspring  4: :+9#T9%~4CE`-8L~K$V(<.?+M7]% -> ,-^??YED8@6\}YW,0[K"1S!1V]Z` (monkey typing)
Generation    1 Offspring  5: UE#@S"C<")${/)]BG:<UT[`YO7J4 -> 8|}WVI}$%/,:]R_PHN9}P4V:5G<( (monkey typing)
...

-rで変異確率を設定できたり、-qで途中出力を省略したりもできる。詳しくはweasel.manを参照のこと。

$ ./prog -qr5
quiet output
target 'METHINKS IT IS LIKE A WEASEL'
mutation rate 5
Generation  733 Offspring 24: METHINKS IT IS LIKE A WEASEL

解説

イタチプログラムとは、リチャード・ドーキンスが著書『盲目の時計職人』で提唱した思考実験らしい。背景には、「猿がタイプライターを無限に叩き続ければ、いつか必ず任意のテキスト（たとえばシェイクスピアの作品でも）を打ち出す」という無限の猿定理がある。シェイクスピアの全文を出すには、当然ものすごく長い時間がかかる。しかし、たとえば”Methinks it is like a weasel”という短い一文をターゲットとし、キーボードを大文字アルファベット26文字とスペースだけの制限されたものにすれば、もっと短い時間でできるのでは？というのがドーキンスのイタチプログラムらしい。ドーキンスは、単純にランダム探索するのではなく、突然変異の中からなるべくターゲットに近い文字列を残すことを繰り返すことで、現実的な時間でたどり着けることを示したとのこと（問題の本は自然選択の本らしい）。

hint.textは実に長大で、1000行以上ある。流し見しかできていない。 hint.textの目次を貼っておく。

まえがき
これはなにか
どのように動くか
ヒント（キーボード、オプション、ネタバレ、実行例）
難読化（技術、美）
ビルド方法（定数SとN、コンパイル、ポータビリティ、インストール）
むすび
勝利のコメント、感謝、献辞、リンクなど

コードは、審査員が提供しているguidelines.txtの中の戯言を細かく拾っている模様。「ペットの魚のEric」を受けて、SIZE_MAX - 1までにターゲットに到達できなかった場合のエラーメッセージを”Too many attempts, blaming the monkey Eric even if he isn’t typing or doesn’t exist. Bye.”にしてみるとか。「2305567963945518424753102147331756070の何が特別か？」というクイズ（答え：2から97までの素数をかけあわせたもの）を受けて、-DN=97というコンパイルオプションを与えたらターゲット文字列がこれになるとか（作者は97の素数階乗素数と言っているが、これは誤解のような気がする）。コードを潰しただけのもの（a compact blob of octets）は好まない、という審査員のヒントに対しては、/*NO*/ /*BLOB*/ /*CODING*/や/*THIS*/ /*IS*/ /*NOT*/ /*A*/ /*COMPACT*/ /*BLOB*/ /*OF*/ /*OCTETS*/というコメントをバラバラに含めておいたとのこと。

キーの種類を減らしたバージョンも配布されている（prog-simple.c）。

manに「イースターエッグが2つある」とあるが、-mオプションと-DN=97のことだと思う。

なお、無限の猿定理自体は[[1989/ovdluhe]]で前例がある。