39337975 9278*:**:*-
39337976 8278*:**:*-
39337977 7278*:**:*-
39337978 6278*:**:*-
39337979 5278*:**:*-
39337980 4278*:**:*-
39337981 3278*:**:*-
39337982 2278*:**:*-
39337983 1278*:**:*-

	private static long sq(long a){
		return a*a;
	}
	private static long pow(int b,int i){
		if(b==4) return 1L<<2*i;
		if(i==0) return 1L;
		if(i==1) return b;
		if((i&1)==1){
			return b*sq(pow(b,i>>>1));
		}else{
			return sq(pow(b,i>>>1));
		}
	}

if n=6
> import itertools
> for item in itertools.permutations(["0"]*2+["1"]*4, 6):
      print(''.join(item),end=" ")

Much faster

for item in set(itertools.permutations(list("001111"))):
    print(''.join(item),end=" ")

Or

for item in sorted(list(set(itertools.permutations(list("001111"))))):
    print(''.join(item),end=" ")

for item in itertools.product(range(2),repeat=12):
    if item.count(1)==4:
        print(''.join(map(str,item)),end=" ")

	private static long next(long a,int n){
		int i=0,j;
		for(;i<n;i++){
			if(((a>>>i)&1)==0) break;
		}
		a = (a>>>i)<<i;
		for(j=i;j<n;j++){
			if(((a>>>j)&1)==1) return a^(((1L<<(i+2))-1)<<(j-i-1));
		}
		return 0;
	}

memory: 000 000 000 000
>>>>++++++++++
memory: 000 000 000 010
<<
++++++++++++++++++++++++
memory: 000 024 000 010
[
[->+>-[>+>]<<<<]
>>>>>[-]
<<[->+<]
<<+>
]
memory: 000 024 000 010