this one is nice, Wordle shaped Wordle program

https://github.com/ioccc-src/winner/blob/master/2024/burton/...

  #include <stdarg.h>
  #include <stdlib.h>
  # include <stdio.h>
  #define J(J) for (\
  _ j=0; j<5; ++j) J;
  #define/*IOCCC*/I \
  \
  \
  \
        _ W,_ O,_ R,_ D,_*L,_*E


   #define A(A  )for(_ j=0;  !o&&j<5&&(k  = t[l][j]);  ++j)A&&++o;
   typedef/* ;  ; */void q;  typedef int  _ ; typedef  char/* */p;
   struct{ p a  [257],b[9][  5],c[5],d[5  ]; _ e,f; }  i;p t[78557
   ][5]; _ s,a  []={ 9,9,9,  10,13,18,27  ,39,55,1,18  ,2,1,1,35,2
   ,19,18,1,52  ,36,35,20,3  ,2,19,18,18  ,69,2,53,1,  52,37,3,20,
   36,19,35,18  ,52,86,2,53  ,70,1,69,38  ,4,21,3,37,  19,36,35,25
   ,10,+17,15,  26,9,11,12,  23,2,06,18,  13,20,22,14  ,1,24,19,21

   ,16,5,7,4,8  ,3},u=' ';_  W(p*a,p*b){  for(p*c=a+5  ;a<c;)*a++=
   *b++;return  0; } _ O(p*  a,p b){ p*c  =a+5; for(;  a<c&&*a-b;)
   ++a; return  a<c?5-(a-c)  :0; } _ R(p  *a, ... ) {  va_list b ;
   va_start(b,  a); vprintf  (a,b); exit  (1); } q D(  p*a){ if (s
   ==sizeof t/  5)R("limit"  " %d\n",s);  p*b=s[t],i,  j; for(i=j=
   0; i<7&&!j;  ++i)if(!(j=  *a==10?i:0)  )*b++=u|* a  ++; j-5||++
   s; } q L(p*  a,_ b){ for  (_ l=0,o=0,  k; l<s; o=0  ){ A(i.c[j]

   &&k-i.c[j])  A(i.a[k])A(  i.d[j]&&!O(  t[l],i.d[j]  ))for(_ f=i
   .e; f--&&!o  ; )A(i.b[f]  [j]==k)if(!  o){ J(o+=t[  l][j]==a[j]
   )o=o==5?b!=  5:0; } o?W(  t[l],t[--s]  ) :++l; } }  _ e(I){ for
   (; O<D; )L[  R++]=E[O+++  D*W];return  R; } q S( _  O,_*l){ for
   (_*s=&a[a[O  ]],*e=a[-~O  ]+s-a[O]; s  <e; ){ _ i=  *s++,j=i&15
   ,k=l[i>>=4]  <l[+j]?k=l[  i],l[i]=l[j  ],l[j]=k:i;  } } _ o(I){
   _ o=0, w=0;  for(; o<D&w  <D; )L[R++]  =E[o+D*W]>=  E[w+D*O]?E[
   o+++D*W]:E[  w +++ D*O];  return e(O,  w,e(W,o,R,D  ,L,E),D,L,E

   ); } q l( _  n,_*f){ for  (_* e=f+26,  i,j; f<e&&*  f>u; f+= i)
   { for(i=1,j  =*f/u; i <n  &&f[i]>>5==  j; )++i;for  (j=0; j <i;
   ++j)f[j] &=  31,f[j]|=a[  f[j]+a[~-9]  ]<<5; S(i,f  ); } } q v(
   _ a,_*w,_*k  ){ o(2,3,o(  0,1,0,a,w,k  ),a,w,k); o  (0,1,0,a+a,
   k,w); l(a,k  ); } p*E(p*  d){ _ l,j,k  =u,b[u] ,c[  k]; p*e[97]
   [5 ]={ 0} ;  for(l=0; l<  k; ++l)c[l]  =l; for(l=0  ; l<s; ++l)
   J(c[t[l][j]  -97]+=k)for  (l= j=7; j<  22; j+=l)S(  l,c+j-l); v

   (l,b,c);for  (l= 0; l<k;  ++l)b[c[l]&  ~-k]=l; for  (k*=3,l= 0;
   l<s; ++l) {  _ i=0; J( i  +=b[t[l][j]  -97])if(i<k  )J(e[i][ j]
   ||(e[i][j]=  t[l],j=4))}  for(l=0; l<  k; ++l)for(  p*b=0,k=j=0
   ; j<5&&(b=e  [l][j]); k=  !++j){ p c[  32]={0} ; d  =*d-120?d:b
   ; if(s>2)J(  k+=++c[b[j]  -97]>1); if  (!k) return  b; } return
   d; } p*r(p*  b){ _ k, l;  for(_ j=k=l  =0; j<5; ++  j) { signed
   char n=b[j]  ,o=b[j-~5]+  ~0x66; (o?i  .b[i.e]:i.c  )[j]=n; !o?

   i.a[n]=!++k  :O(i.d,n)||  (*(o<0?&i.a  [n]:&i.d[i.  f++])=l=n);
   } i.e += !!  l; L(b, k);  return E(""  "xyzzy"); }  _ main(_ n,
   char**v){ p  *j=i .c-97,  *l=j-11; n-  2?R("usage"  ": %s dict"
   "\n",* v):5  ; ; FILE*k=  fopen(*++v,  "r"); if(!k  ) return //
   perror(*v),  1; ; while(  fgets(j, u^  n,k)) D(j);  fclose (k);
   ; ; setbuf(  stdout, 0);  while(~-s){  printf("? "  ); while(~(
   n=getchar()  )&&n-10&&l<  j)*l++=n; l  <j&&R("inp"  "ut: guess"
   " color\n")  ;printf("%"  ".5s\n",r(l  =j+~10)); }  return 0; }