#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include "lceb.h"

void gen_tree(seq, n, nb1, nb0)
    int *seq;
    int n;                      /* number of nodes */
    int nb1;                    /* number of "1" */
    int nb0;                    /* number of "0" */
{
    int i;

     if((nb1 + nb0) == 2*n) {   /* end */
        seq[2*n] = 0;
        printf("tree=");
        for (i=0; i<=2*n; ++i)
            printf("%d", seq[i]);
        putchar('\n');
        return;
     }

    if(nb1 >= nb0 && nb1 < n) {
        seq[nb1+nb0] = 1;
        gen_tree(seq, n, nb1+1, nb0);
    }

    if(nb0 < nb1 && nb1 <=n) {
        seq[nb1+nb0] = 0;
        gen_tree(seq, n, nb1, nb0+1);
    }
}

#ifdef STANDALONE
main(ac, av)
    int ac;
    char **av;
{
    int n;
    int array[1024];
    n=atoi(av[1]);
    gen_tree(array, n, 0, 0);
    exit(0);
}
#endif