Give it an input and say what you think comes back. It compiles and runs for real, so a wrong guess still shows you the answer — probe as much as you like. Only correct predictions count.
Locked until you have predicted 3 outputs correctly.
| 1 | void build(vector<int>& nums, int i, vector<vector<int>>& out) { |
| 2 | int n = nums.size(); |
| 3 | if (i == n) { |
| 4 | out.push_back(nums); |
| 5 | return; |
| 6 | } |
| 7 | |
| 8 | for (int j = i; j < n; j++) { |
| 9 | swap(nums[i], nums[j]); |
| 10 | build(nums, i + 1, out); |
| 11 | swap(nums[i], nums[j]); |
| 12 | } |
| 13 | } |
| 14 | |
| 15 | vector<vector<int>> solution(vector<int> nums) { |
| 16 | vector<vector<int>> out; |
| 17 | build(nums, 0, out); |
| 18 | return out; |
| 19 | } |
Names have been stripped. The signature is the only clue you get for free. Compiled as C++20 with the standard headers and using namespace std; already in scope.