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Efficiently Removing Duplicates from an Array Without Resorting to Set
You have endeavored to create a customized solution for eliminating duplicate elements from an array, but performance bottlenecks have emerged. To optimize this implementation, we will analyze the shortcomings of your approach and propose alternative strategies.
Analysis of Your Algorithm
Your algorithm attempts to search for duplicates by comparing each element with every subsequent element. This exhaustive comparison results in an O(n^2) time complexity. For large arrays, this strategy can become extremely inefficient.
Optimized Approach
To significantly improve performance, we can consider the following optimization:
Alternative Solutions
While the aforementioned optimizations can enhance your algorithm's performance, you may also consider other established techniques:
Implementation
Based on the optimized approach, a modified version of your algorithm utilizing a hash map could be:
public static int[] removeDuplicatesWithoutSet(int[] arr) { HashMap<Integer, Boolean> map = new HashMap<>(); int end = arr.length; for (int i = 0; i < end; i++) { if (map.containsKey(arr[i])) { int shiftLeft = i; for (int k = i + 1; k < end; k++, shiftLeft++) { arr[shiftLeft] = arr[k]; } end--; i--; } else { map.put(arr[i], true); } } int[] whitelist = new int[end]; for (int i = 0; i < end; i++) { whitelist[i] = arr[i]; } return whitelist; }
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