Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).

Given a set of distinct integers, nums, return all possible subsets (the power set).

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.