Bob and Pallindromes

CodeChefRating 2060Open on judge ↗

Bob has a string (S), which is initially empty. In one operation, he can select a lowercase character (a-z) uniformly at random and appends it to S. He then evaluates whether S is a palindrome or not; if it is, he gets 1 point. Given that Bob performs N operations in total, find the expected no. of points Bob gets. It is guaranteed that the answer can always be represented as a rational number $

HINT LADDERno hints yet

L1 Observation

L2 Technique

L3 Approach

L4 Pseudo-code

🔒

L5 Full solution

L5 unlocks only if you insist twice

solution.cppC++17

CodeSearch Tutor

Hints, not spoilers — it won’t hand over the full solution unless you insist.

voice by Sarvam AI