test30.py

SPACE = '   '

def subsets(nums):
    res = []

    def dfs(temp, idx):
        print(f"{idx * SPACE}entering dfs({temp},{idx})")
        res.append(temp[:])
        print(f"{idx * SPACE}res:{res}")

        print(f"{idx * SPACE}entering loop")
        for i in range(idx, len(nums)):
            temp.append(nums[i])
            print(f"{i * SPACE}temp:{temp} i:{i} before recursive call")
            dfs(temp,i +1)
            print(f"{i * SPACE}temp:{temp} i:{i} before backtrack")
            temp.pop()
            print(f"{i * SPACE}temp:{temp} i:{i} after backtrack")

        print(f"{idx * SPACE}exiting loop")

    dfs([], 0)
    print("exiting dfs")

    return res

print(f"\nsubsets: {subsets([1,2,3])}")