#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <time.h>
int *d;
int n,m,i,a,b,t;
int main() {
srand ( time (NULL));
while (1) {
printf ( "Input n m(n>=m>0):" ); fflush (stdout);
rewind (stdin);
if (2== scanf ( "%d%d" ,&n,&m)) {
if (n>=m && m>0) break ;
}
}
d=( int *) malloc ((n+1)* sizeof ( int ));
if (NULL==d) return 1;
for (i=0;i<=n;i++) d[i]=i;
for (i=n+1;i>0;i--) {
a=i-1;b= rand ()%i;
if (a!=b) {t=d[a];d[a]=d[b];d[b]=t;}
}
for (i=0;i<m;i++) printf ( "%2d " ,d[i]);
printf ( "\n" );
free (d);
return 0;
}