Think twice, code once.

摘要： class Solution: def permute(self, nums: List[int]) -> List[List[int]]: res = [] n = len(nums) def per(nums,start): if start == n-1: res.append(nums[:] 阅读全文

摘要： # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self. 阅读全文