I created a video that talks about 6 problems involving RBS.

• Level 0 : Check if string is RBS
• Level 1 : Length of longest RBS
• Level 2 : Count of RBS substrings
• Level 3 : Is a substring S[L...R] RBS?
• Level 4 : Flip each element in S[L...R]. Is the original string RBS?
• Level 5 : How many (L, R) can be flipped such that original string is still RBS?

I discuss some approaches using DP, Stack, Contribution Technique, Binary Search, Segment Tree, Binary Search inside segment tree, fast lookup of zero sum subarrays, etc.

Practice Problems :

• Longest Regular Bracket Sequence
• Invertible Bracket Sequences