leetcode: 78. Subsets

Problem

# Given a set of distinct integers, nums, return all possible subsets (the power set).
#
# Note: The solution set must not contain duplicate subsets.
#
# For example,
# If nums = [1,2,3], a solution is:
#
# [
#   [3],
#   [1],
#   [2],
#   [1,2,3],
#   [1,3],
#   [2,3],
#   [1,2],
#   []
# ]

AC

class Solution():
def subsets(self, x):
if not x:
return [[]]
else:
last = x[-1]
tmp = self.subsets(x[:-1])
tmp2 = [i + [last] for i in tmp]
return tmp + tmp2

if __name__ == "__main__":
assert Solution().subsets([1, 2, 3]) == [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]

class Solution():
def subsets(self, x):
res = [[]]
if x:
x.sort()
for i in range(len(x)):
for j in range(len(res)):
res.append(res[j]+[x[i]])
return res

if __name__ == "__main__":
assert Solution().subsets([1, 2, 3]) == [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]