Medium
Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.
Example 1:
Input: nums = [1,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
Example 2:
Input: nums = [0,1]
Output: [[0,1],[1,0]]
Example 3:
Input: nums = [1]
Output: [[1]]
Constraints:
1 <= nums.length <= 6-10 <= nums[i] <= 10- All the integers of
numsare unique.
#include <vector>
class Solution {
public:
std::vector<std::vector<int>> permute(std::vector<int>& nums) {
if (nums.empty()) {
return {};
}
std::vector<std::vector<int>> finalResult;
std::vector<int> currResult;
std::vector<bool> used(nums.size(), false);
permuteRecur(nums, finalResult, currResult, used);
return finalResult;
}
private:
void permuteRecur(const std::vector<int>& nums,
std::vector<std::vector<int>>& finalResult,
std::vector<int>& currResult,
std::vector<bool>& used) {
if (currResult.size() == nums.size()) {
finalResult.push_back(currResult);
return;
}
for (size_t i = 0; i < nums.size(); ++i) {
if (used[i]) {
continue;
}
currResult.push_back(nums[i]);
used[i] = true;
permuteRecur(nums, finalResult, currResult, used);
used[i] = false;
currResult.pop_back();
}
}
};