# Check if all array elements are distinct

• Difficulty Level : Basic
• Last Updated : 16 Jun, 2021

Given an array, check whether all elements in an array are distinct or not.
Examples:

```Input : 1, 3, 2, 4
Output : Yes

Input : "Geeks", "for", "Geeks"
Output : No

Input : "All", "Not", "Equal"
Output : Yes```

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One simple solution is to use two nested loops. For every element, check if it repeats or not. If any element repeats, return false. If no element repeats, return false.
An efficient solution is to Hashing. We put all array elements in a HashSet. If size of HashSet remains same as array size, then we return true.

## C++

 `// C++ program to check if all array``// elements are distinct``#include ``using` `namespace` `std;` `bool` `areDistinct(vector<``int``> arr)``{``    ``int` `n = arr.size();` `    ``// Put all array elements in a map``    ``unordered_set<``int``> s;``    ``for` `(``int` `i = 0; i < n; i++) {``        ``s.insert(arr[i]);``    ``}` `    ``// If all elements are distinct, size of``    ``// set should be same array.``    ``return` `(s.size() == arr.size());``}` `// Driver code``int` `main()``{``    ``std::vector<``int``> arr = { 1, 2, 3, 2 };` `    ``if` `(areDistinct(arr)) {``        ``cout << ``"All Elements are Distinct"``;``    ``}``    ``else` `{``        ``cout << ``"Not all Elements are Distinct"``;``    ``}` `    ``return` `0;``}`

## Java

 `// Java program to check if all array elements are``// distinct or not.``import` `java.util.Arrays;``import` `java.util.HashSet;``import` `java.util.Set;` `public` `class` `DistinctElements {``    ``public` `static` `boolean` `areDistinct(Integer arr[])``    ``{``        ``// Put all array elements in a HashSet``        ``Set s =``           ``new` `HashSet(Arrays.asList(arr));` `        ``// If all elements are distinct, size of``        ``// HashSet should be same array.``        ``return` `(s.size() == arr.length);``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``Integer[] arr = { ``1``, ``2``, ``3``, ``2` `};``        ``if` `(areDistinct(arr))``            ``System.out.println(``"All Elements are Distinct"``);``        ``else``            ``System.out.println(``"Not all Elements are Distinct"``);``    ``}``}`

## Python3

 `# Python3 program to check if all array``# elements are distinct``def` `areDistinct(arr) :` `    ``n ``=` `len``(arr)` `    ``# Put all array elements in a map``    ``s ``=` `set``()``    ``for` `i ``in` `range``(``0``, n):``        ``s.add(arr[i])``    ` `    ``# If all elements are distinct,``    ``# size of set should be same array.``    ``return` `(``len``(s) ``=``=` `len``(arr))` `# Driver code``arr ``=` `[ ``1``, ``2``, ``3``, ``2` `]` `if` `(areDistinct(arr)):``    ``print``(``"All Elements are Distinct"``)` `else` `:``    ``print``(``"Not all Elements are Distinct"``)` `# This code is contributed by ihritik`

## C#

 `// C# program to check if all array elements are``// distinct or not.``using` `System;``using` `System.Collections.Generic;` `public` `class` `DistinctElements``{``    ``public` `static` `bool` `areDistinct(``int` `[]arr)``    ``{``        ``// Put all array elements in a HashSet``        ``HashSet<``int``> s = ``new` `HashSet<``int``>(arr);` `        ``// If all elements are distinct, size of``        ``// HashSet should be same array.``        ``return` `(s.Count == arr.Length);``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main(String[] args)``    ``{``        ``int``[] arr = { 1, 2, 3, 2 };``        ``if` `(areDistinct(arr))``            ``Console.WriteLine(``"All Elements are Distinct"``);``        ``else``            ``Console.WriteLine(``"Not all Elements are Distinct"``);``    ``}``}` `// This code has been contributed by 29AjayKumar`

## Javascript

 ``
Output:
`Not all Elements are Distinct`

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