我們如何產生整數數組的所有唯一排列？

int[] a = {3, 4, 6, 2, 1};

for (int i = 0; i < a.length; i++) {
  // Perform actions for each element of the array
  for (int j = i + 1; j < a.length; j++) {
    // Swap elements at indices i and j to generate a permutation
    int temp = a[i];
    a[i] = a[j];
    a[j] = temp;

    // Check if the current permutation has already been generated
    if (!hasBeenGenerated(a)) {
      // If the permutation is new, add it to the list of permutations
      addPermutationToList(a);
    }

    // Swap the elements back to restore the original array
    temp = a[i];
    a[i] = a[j];
    a[j] = temp;
  }
}