LeetCode|46.排列的所有可能组合 LeetCode|C++

Permutations 问题描述： 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],
[3,2,1]
]
参考答案：

class Solution { public: vector > permute(vector &num) { vector > result; permuteRecursive(num, 0, result); return result; }// permute num[begin..end] // invariant: num[0..begin-1] have been fixed/permuted void permuteRecursive(vector &num, int begin, vector > &result){ if (begin >= num.size()) { // one permutation instance result.push_back(num); return; }for (int i = begin; i < num.size(); i++) { swap(num[begin], num[i]); permuteRecursive(num, begin + 1, result); // reset swap(num[begin], num[i]); } } };

性能： 【LeetCode|46.排列的所有可能组合】