Remove duplicates from sorted array

Problem

Given an integer array nums sorted in non-decreasing order, remove all duplicates in-place so that each unique element appears only once. Return the number of unique elements in the array.

If the number of unique elements be k, then,

• Change the array nums such that the first k elements of nums contain the unique values in the order that they were present originally.
• The remaining elements, as well as the size of the array does not matter in terms of correctness.

An array sorted in non-decreasing order is an array where every element to the right of an element in either equal to or greater in value than that element.

Examples

Input: nums = [0, 0, 3, 3, 5, 6]

Output: [0, 3, 5, 6, _, _]

Explanation: There are 4 distinct elements in nums and the elements marked as _ can have any value.

Input: nums = [-2, 2, 4, 4, 4, 4, 5, 5]

Output: [-2, 2, 4, 5, _, _, _, _]

Explanation: There are 4 distinct elements in nums and the elements marked as _ can have any value.

Solution

class Solution {
  public int removeDuplicates(int[] nums) {
    if (nums.length == 0) {
      return 0;
    }

    int i = 0;

    for (int j = 1; j < nums.length; j++) {
      if (nums[i] != nums[j]) {
        i++;
        nums[i] = nums[j];
      }
    }

    return i + 1;
  }
}