28. Remove Duplicates in Array

The problem can be found at the following link: Question Link

Problem Description

Given an array arr consisting of positive integer numbers, remove all duplicate numbers. The modified array should contain only unique elements.

Example:

Input:

arr[] = [2, 2, 3, 3, 7, 5]

Output:

[2, 3, 7, 5]

Explanation: After removing the duplicates 2 and 3, we get the array [2, 3, 7, 5].

Input:

arr[] = [2, 2, 5, 5, 7, 7]

Output:

[2, 5, 7]

Input:

arr[] = [8, 7]

Output:

[8, 7]

Constraints:

• 1 ≤ arr.size() ≤ 10^6

• 2 ≤ arr[i] ≤ 100

My Approach

1. Using a Set for Uniqueness:

   • Utilize a set to keep track of the unique elements encountered while iterating through the array. Sets automatically handle duplicates for us.

2. Building the Result:

   • Iterate through the array, adding elements to the set. If an element is already present in the set, it is ignored.

   • Finally, convert the set back to a vector or array for the result.

Time and Auxiliary Space Complexity

• Expected Time Complexity: O(n), where n is the length of the input array. Each element is processed once.

• Expected Auxiliary Space Complexity: O(n), as we use a set to store the unique elements.

Code (C++)

class Solution {
public:
    vector<int> removeDuplicate(vector<int>& arr) {
        vector<int> result;
        unordered_set<int> seen;

        for (int num : arr) {
            if (seen.insert(num).second) {
                result.push_back(num);
            }
        }
        return result;
    }
};

Code (Java)

class Solution {
    ArrayList<Integer> removeDuplicate(int arr[]) {
        ArrayList<Integer> result = new ArrayList<>();
        HashSet<Integer> seen = new HashSet<>();

        for (int num : arr) {
            if (seen.add(num)) {
                result.add(num);
            }
        }
        return result;
    }
}

Code (Python)

class Solution:
    def removeDuplicates(self, arr):
        seen = set()
        result = []
        for num in arr:
            if num not in seen:
                result.append(num)
                seen.add(num)
        return result

Contribution and Support

For discussions, questions, or doubts related to this solution, please visit my LinkedIn: Any Questions. Thank you for your input; together, we strive to create a space where learning is a collaborative endeavor.

⭐ Star this repository if you find it helpful or intriguing! ⭐

📍Visitor Count