RecursionBacktracking
Print every binary string of length n (strings made of 0 and 1) in ascending lexicographic order, one per line.
Input
A single integer n.
Output
2^n lines, each a binary string of length n, in ascending order.
Constraints
1 <= n <= 12
Example 1
Input
2
Output
00 01 10 11
The four strings in order: 00, 01, 10, 11.