Language: C

w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'w' [-Wimplicit-int]
main.c:1:7: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |       ^
main.c:1:9: error: return type defaults to 'int' [-Wimplicit-int]
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |         ^~~~
main.c: In function 'main':
main.c:1:9: error: type of 'd' defaults to 'int' [-Wimplicit-int]
main.c:1:28: error: expected ';' before ')' token
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |                            ^
      |                            ;
main.c:1:53: error: implicit declaration of function 'getchar' [-Wimplicit-function-declaration]
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |                                                     ^~~~~~~
main.c:1:1: note: 'getchar' is defined in header '<stdio.h>'; this is probably fixable by adding '#include <stdio.h>'
  +++ |+#include <stdio.h>
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
main.c:1:179: error: implicit declaration of function 'putchar' [-Wimplicit-function-declaration]
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |                                                                                                                                                                                   ^~~~~~~
main.c:1:179: note: include '<stdio.h>' or provide a declaration of 'putchar'
main.c:1:281: error: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
    1 | w[25],i;main(d){for(i<9;i++){if(i&1)for(d=0;d<5;d++)getchar()-'0'?w[i/2*5+d]|=2,w[i/2*5+d+5]|=8:0;else for(d=0;d<4;d++)getchar()-'0'?w[i/2*5+d]|=1,w[i/2*5-~d]|=4:0;getchar();}d=!putchar(82);for(i=1;d|i;d&=3)w[i]&1<<d?i+="GKEA"[d]-70,putchar("RDLU"[d]),w[i]&1<<(d+3&3)&&--d:++d;i=!puts("");}
      |                                                                                                                                                                                                                                                                                         ^~~~
main.c:1:281: note: include '<stdio.h>' or provide a declaration of 'puts'