#Dsa 2

Discuss and solve a BFS problem that is similar to the Bus Routes problem, though the exact question details were not remembered.

Implement a function to reverse a linked list in groups of size k. For example, given the linked list A → B → C → D → E and k = 2, the output should be B → A → D → C → E. If the remaining nodes are less than k, they should remain unchanged.

Solve a medium-level tree traversal problem.

Solve a variation of the Longest Repeating Character Replacement problem.

Find the longest zigzag path in a binary tree. A zigzag path is defined as one where the direction alternates between left and right. **Approach**: Track the previous direction and current length. If the last move was to the left, the next must be to the right, and vice versa.