add shuffle function
add shuffle function

nomeata/codeworld,xwysp/codeworld,google/codeworld,three/codeworld,pranjaltale16/codeworld,pranjaltale16/codeworld,three/codeworld,tgdavies/codeworld,d191562687/codeworld,parvmor/codeworld,parvmor/codeworld,alphalambda/codeworld,d191562687/codeworld,tgdavies/codeworld,tgdavies/codeworld,nomeata/codeworld,pranjaltale16/codeworld,stefan-j/codeworld,stefan-j/codeworld,alphalambda/codeworld,d191562687/codeworld,alphalambda/codeworld,Ye-Yong-Chi/codeworld,google/codeworld,venkat24/codeworld,stefan-j/codeworld,xwysp/codeworld,Ye-Yong-Chi/codeworld,google/codeworld,Ye-Yong-Chi/codeworld,venkat24/codeworld,nomeata/codeworld,three/codeworld,xwysp/codeworld,venkat24/codeworld,parvmor/codeworld