Permutations 2021-06-06 04:04
public static List<List<Integer>> permute(int[] nums) {
List<List<Integer>> l = new LinkedList<>();
permute(nums, 0, l);
return l;
}
private static void permute(int[] nums, int p, List<List<Integer>> l) {
if (p + 1 == nums.length) {
List<Integer> ll = new LinkedList<>();
for (int num : nums) {
ll.add(num);
}
l.add(ll);
return;
}
for (int i = p; i < nums.length; i++) {
swap(nums, p, i);
permute(nums, p + 1, l);
swap(nums, p, i);
}
}
private static void swap(int[] nums, int i, int j) {
if (i == j) {
return;
}
int tmp = nums[i];
nums[i] = nums[j];
nums[j] = tmp;
}
| Runtime | Memory |
|---|---|
| 0 ms | 39 MB |
EOF