1 Strings Reverse a string Very easy 2m 15s

3 Arrays Double an array Easy 2m 15s

23 Arrays Find the missing number Medium 7h 2m 3s

652 Binary Search Preorder traversal Hard 7h 2m 3s

652 Binary Search Preorder traversal Very hard 7h 2m 3s

652 Binary Search Preorder traversal Insane 7h 2m 3s

652 Traversal Get kth tree in nth node in preorder traversal Elite 7h 2m 3s