h2. Additional problems

# Given a string of length n, count the number of palindromic subsequences of S. Solve better than O(n^2^).

# Given a string of length n, count the number of palindromic substring of S. Solve better than O(n^2^).

# Given a string of length n, find the longest substring that is repeated at least k times. Solve in O(n log n)
# Given a bitmap, find out the largest square that’s repeated in the bitmap.
# Given a string S figure out if the string is periodic. (there is a p such that for any i we have that s[i] == s[i + p]) For example abcabcab is periodic with p = 3. O(n log n)