1. No of continuos 1s in an array with atmost one swap
2. Jump stair case problem with a variation that you could jump 3 steps atmost k times
3. Finding and removing a loop in the linkedlist
4. Boundary traversal of tree
5. LRU cache implimentation
6. buy and selling stocks atmost k times
practice from geeksforgeeks previous question. It helped me alot.