How to efficiently remove duplicates from an array without using Set

Question

I was asked to write my own implementation to remove duplicated values in an array. Here is what I have created. But after tests with 1,000,000 elements it took very long ti

Answer 1

Not a big fun of updating user input, however considering your constraints...

public int[] removeDup(int[] nums) {
  Arrays.sort(nums);
  int x = 0;
  for (int i = 0; i < nums.length; i++) {
    if (i == 0 || nums[i] != nums[i - 1]) {
    nums[x++] = nums[i];
    }
  }
  return Arrays.copyOf(nums, x);
}

Array sort can be easily replaced with any nlog(n) algorithm.