# Minimum Repeated Substring

**Logic**Level 3

A binary string is called *repeated* if it is even in length and its first half is identical to its last half. For example, the string \(\text{100100, 0101, 00, 010010}\) are *repeated* string.

What is the minimum number of **unique** repeated substring one can have with a binary string of length 18?

**Details and Assumptions**

- The string \(\text{000101}\) has 2 unique repeated substrings \(\text{00, 0101}\).