How to Efficiently Remove Duplicates from a Sorted Array in Java While Maintaining Order?
I've encountered a strange issue with I'm converting an old project and I'm getting frustrated with After trying multiple solutions online, I still can't figure this out... I'm working on a Java application that processes large datasets, and I need to remove duplicates from a sorted array while maintaining the original order of the unique elements. My current approach is to use a `HashSet` to keep track of seen elements, but I'm concerned about the performance, especially with large arrays. Here’s what I’ve tried: ```java public class RemoveDuplicates { public static int removeDuplicates(int[] nums) { if (nums.length == 0) return 0; Set<Integer> seen = new HashSet<>(); int uniqueCount = 0; for (int num : nums) { if (!seen.contains(num)) { seen.add(num); nums[uniqueCount++] = num; } } return uniqueCount; } } ``` While this works, I'm getting performance complaints when processing arrays with more than 100,000 elements. The current approach has a space complexity of O(n) due to the `HashSet`, which I think could be improved. Additionally, when the input array is empty, I’m unsure if I’m handling it correctly, as the method returns 0, but I still see the original array being modified. I also experimented with a two-pointer technique which seems promising but I'm unsure how to implement it effectively. Here's a rough idea I had: ```java public static int removeDuplicatesTwoPointers(int[] nums) { if (nums.length == 0) return 0; int uniqueCount = 1; for (int i = 1; i < nums.length; i++) { if (nums[i] != nums[i - 1]) { nums[uniqueCount++] = nums[i]; } } return uniqueCount; } ``` However, when I test this with an array like `{1, 1, 2, 2, 3}`, it correctly keeps the order, but I’m worried about edge cases where all elements are duplicates or if the array has only one unique number. Can someone suggest a more efficient way or confirm if the two-pointer approach is valid for my case? Any insights on the performance implications would also be appreciated. Thanks! How would you solve this? I'm working with Java in a Docker container on macOS. Thanks, I really appreciate it! The project is a CLI tool built with Java. Any help would be greatly appreciated! For reference, this is a production desktop app. Any ideas what could be causing this?