You now know four major knapsack variations:
Boolean/Subset Sum: = can we reach sum ? Used in partition and target sum problems.
Counting: = how many ways? Watch loop order for combinations vs permutations.
Bounded: Binary decomposition converts copies to items.
Multi-dimensional: Add dimensions to the DP array for each constraint. Combined with 0/1 and unbounded knapsack from the previous section, you now have the full toolkit. Practice identifying which variation applies. That recognition skill is what separates fast problem-solvers from slow ones.