http://www.lintcode.com/en/problem/permutations/# Given a list of numbers, return all possible permutations. Example For nums = [1,2,3], the permutations are: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ] 求全排列,可以使用DFS来解决,来看代码: class Soluti…