Algorithms to work on after Leetcode 377 combinations IV

I like to go over those Leetcode algorithms:

39, 40, 216, 322, 518, 474.

Leetcode 39: combination sum ( medium level)
Leetcode 40: combination sum II (medium level)
Leetcode 216: combination sum III (medium level)
Leetcode 322: coin change (medium level)
Leetcode 518: coin change 2 (medium level)
Leetcode 474: Ones and Zeros (medium level)