Given a collection of distinct numbers, return all possible permutations.
For example,
[1,2,3] have the following permutations:
[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].
题意:
给一组离散的数字,返回所有组合形式
参考:
http://www.cnblogs.com/zuoyuan/p/3758816.html
思路:
递归:提出 i,剩余的 nums[:i]+nums[i+1:] 去递归组合
Python
class Solution(object):
def permute(self, nums):
"""
:type nums: List[int]
:rtype: List[List[int]]
"""
if len(nums)==0:
return []
if len(nums)==1:
return [nums]
ans=[]
for i in range(len(nums)):
for j in self.permute(nums[:i]+nums[i+1:]):
ans.append([nums[i]]+j)
return ans