Recursion and Backtracking

Define a backtracking template with a clear base case, recursive step, and state reversal.

Apply backtracking to generate combinatorial objects like subsets, permutations, and combinations.

Solve the N-Queens problem using backtracking with pruning.

Solve grid-based problems like word search or finding paths in a maze using backtracking.

Introduce memoization to optimize overlapping subproblems in recursive solutions.