Remove duplicates from unsorted array using Set data structure
Given an unsorted array of integers, print the array after removing the duplicate elements from it. We need to print distinct array elements according to their first occurrence.
Examples:
Input: arr[] = { 1, 2, 5, 1, 7, 2, 4, 2} Output: 1 2 5 7 4 Explanation: {1, 2} appear more than one time. Input: arr[] = { 3, 3, 4, 1, 1} Output: 3 4 1
Approach:
- Take a Set
- Insert all array element in the Set. Set does not allow duplicates and sets like LinkedHashSet maintains the order of insertion so it will remove duplicates and elements will be printed in the same order in which it is inserted.
- Convert the formed set into array.
- Print elements of Set.
Below is the implementation of the above approach:
C++
// CPP program to remove duplicates // from unsorted array #include<bits/stdc++.h> using namespace std; // Function to remove duplicate from array void removeDuplicates( int arr[], int n) { set< int > s; // adding elements to LinkedHashSet for ( int i = 0; i < n; i++) s.insert(arr[i]); // Print the elements of LinkedHashSet cout << "[ " ; for ( auto x:s) cout << x << " " ; cout << "]" ; } // Driver code int main() { int arr[] = { 1, 2, 5, 1, 7, 2, 4, 2 }; int n = sizeof (arr) / sizeof (arr[0]); removeDuplicates(arr, n); } // This code is contributed // by Surendra_Gangwar |
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Java
// Java program to remove duplicates // from unsorted array import java.util.*; class GFG { // Function to remove duplicate from array public static void removeDuplicates( int [] arr) { LinkedHashSet<Integer> set = new LinkedHashSet<Integer>(); // adding elements to LinkedHashSet for ( int i = 0 ; i < arr.length; i++) set.add(arr[i]); // Print the elements of LinkedHashSet System.out.print(set); } // Driver code public static void main(String[] args) { int arr[] = { 1 , 2 , 5 , 1 , 7 , 2 , 4 , 2 }; removeDuplicates(arr); } } |
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Python3
# Python3 program to remove duplcates def removeDulipcates(arr): s = dict () d = [] for i in arr: if i not in s.keys(): # Adding elements to the dictionary d.append(i) s[i] = 1 # Printing the dictionary print (d) # Driver Code arr = [ 1 , 2 , 5 , 1 , 7 , 2 , 4 , 2 ] removeDulipcates(arr) # This code is contributed # by Mohit Kumar |
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C#
// C# program to remove duplicates // from unsorted array using System; using System.Collections.Generic; class GFG { // Function to remove duplicate from array public static void removeDuplicates( int [] arr) { HashSet< int > set = new HashSet< int >(); // adding elements to LinkedHashSet for ( int i = 0; i < arr.Length; i++) set .Add(arr[i]); // Print the elements of HashSet foreach ( int item in set ) Console.Write(item + ", " ); } // Driver code public static void Main(String[] args) { int []arr = { 1, 2, 5, 1, 7, 2, 4, 2 }; removeDuplicates(arr); } } // This code is contributed by 29AjayKumar |
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Output:
[1, 2, 5, 7, 4]
Time Complexity: O(N)
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