Permutations.cpp

class Solution {
    public List<List<Integer>> permute(int[] nums) {
        List<List<Integer>> res = new LinkedList<>();
        boolean[] visited = new boolean[nums.length];
        dfs(nums, res, new LinkedList<Integer>(), visited);
        return res;
    }
    private void dfs(int[] nums, List<List<Integer>> res, List<Integer> curr, boolean[] visited) {
        if (curr.size() == nums.length) {
            res.add(new LinkedList<Integer>(curr));
            return;
        }
        for (int i = 0; i < nums.length; i ++) {
            if (visited[i] == false) {
                visited[i] = true;
                curr.add(nums[i]);
                dfs(nums, res, curr, visited);
                curr.remove(curr.size() - 1);
                visited[i] = false;
            }
        }
    }
}