Given a string, find if there is any sub-sequence that repeats itself.
A sub-sequence of a string is defined as a sequence of characters generated by deleting some characters in the string without changing the order of the remaining characters.
0/1 0 -> No 1 -> Yes
abab ------> yes, ab is repeated. So, return 1. abba ------> No, a and b follow different order. So, return 0.
NOTE : sub-sequence length should be greater than or equal to 2