题目描述
链接:https://leetcode-cn.com/problems/subsets/
思路:
一开始想通过切片来实现,但后来发现不太好弄,因为不好控制步长。
代码
class Solution:
def subsets(self, nums):
self.res =
[]
self.backtrack([], 0, nums)
return self.res
def backtrack(self, sol, index, nums):
self.res.append(sol)
for i in range(index, len(nums)):
self.backtrack(sol+[nums[i]], i+1, nums)
(这个是调用过后唯一看懂是咋回事的)
class Solution:
def subsets(self, nums):
n = len(nums)
res_len = 1 << n
res = []
for i in range(res_len):
cur = []
for j in range(n):
a=i >> j & 1
if a:
cur.append(nums[j])
res.append(cur)
return res