#include <fstream>
typedef unsigned char C;unsigned W,O,u=256,i,l,K,b,a[256],R=-1;main(int,char**V
){C*t=new C[1<<24];ifstream g(V[2]);ofstream o(V[3]);if(*V[1]-68){for(;(i=g.get
())<256;K=W,l++){for(b=0;b<i;W+=R/u*(a[b++]+1));if(K>W)for(K=O;!++t[--K];);for(
R=R/u++*(1+a[i]++);R<1<<24;R<<=8)t[O++]=W>>24,W<<=8;}o.write(&l,4);o.write(t,O)
;o<<C(W>>24)<<C(W>>16)<<C(W>>8)<<C(W);}else{g.read(&l,4);g.read(t,4);for(W=*t<<
24|t[1]<<16|t[2]<<8|t[3];i<l;R*=++a[b]){for(K=b=0;R<1<<24;R<<=8,O++)W=W<<8|g.
get();for(R/=u++;W/R>=K;K+=a[b++]+1);W-=R*(K-a[t[i++]=--b]-1);}o.write(t,l);}}

８行まで縮みました