Round 1
Questions: You have been given a string s. Two strings s1 and s2 are considered to be magical string pairs if the number of distinct characters in s1 is equal to s2. Given a string s, find the number of triplets i, j, k which satisfy this condition. The string s1 is from s[i, j] and s2 from [j+1, k].
Candidate's Approach
- Provided a brute force solution using set.
- Offered an optimized solution using BitMask.
- Received hints from the interviewer suggesting the use of Binary Search but was unable to fully implement it.
Interviewer's Feedback
- The interviewer mentioned there is another efficient approach apart from BitMask.
- Provided hints to guide the candidate towards using Binary Search.