Dynamic Programming, Programming, Algorithms, Data, Coding Interviews.
"ABC" which has three characters. If we take 1 when character is part of the subsequence and take 0 not part of the subsequence. Then we can generate all 8 subsequences by masking the input string with the bits of all 3 size bianry numbers. A B C 0 0 0 => Empty 0 0 1 => C 0 1 0 => B 0 1 1 => BC 1 0