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# Find relative complement of two sorted arrays

• Difficulty Level : Easy
• Last Updated : 07 Apr, 2021

Given two sorted arrays arr1 and arr2 of size m and n respectively. We need to find relative complement of two array i.e, arr1 – arr2 which means that we need to find all those elements which are present in arr1 but not in arr2.
Examples:

```Input : arr1[] = {3, 6, 10, 12, 15}
arr2[] = {1, 3, 5, 10, 16}
Output : 6 12 15
The elements 6, 12 and 15 are present
in arr[], but not present in arr2[]

Input : arr1[] = {10, 20, 36, 59}
arr2[] = {5, 10, 15, 59}
Output : 20 36```

1. Take two pointers i and j which traverse through arr1 and arr2 respectively.
2. If arr1[i] element is smaller than arr2[j] element print this element and increment i.
3. If arr1 element is greater than arr2[j] element then increment j.
4. otherwise increment i and j.

## C++

 `// CPP program to find all those``// elements of arr1[] that are not``// present in arr2[]``#include ``using` `namespace` `std;` `void` `relativeComplement(``int` `arr1[], ``int` `arr2[],``                               ``int` `n, ``int` `m) {` `  ``int` `i = 0, j = 0;``  ``while` `(i < n && j < m) {` `    ``// If current element in arr2[] is``    ``// greater, then arr1[i] can't be``    ``// present in arr2[j..m-1]``    ``if` `(arr1[i] < arr2[j]) {``      ``cout << arr1[i] << ``" "``;``      ``i++;` `    ``// Skipping smaller elements of``    ``// arr2[]``    ``} ``else` `if` `(arr1[i] > arr2[j]) {``      ``j++;` `    ``// Equal elements found (skipping``    ``// in both arrays)``    ``} ``else` `if` `(arr1[i] == arr2[j]) {``      ``i++;``      ``j++;``    ``}``  ``}` `  ``// Printing remaining elements of``  ``// arr1[]``  ``while` `(i < n)``    ``cout << arr1[i] << ``" "``; ``}` `// Driver code``int` `main() {``  ``int` `arr1[] = {3, 6, 10, 12, 15};``  ``int` `arr2[] = {1, 3, 5, 10, 16};``  ``int` `n = ``sizeof``(arr1) / ``sizeof``(arr1);``  ``int` `m = ``sizeof``(arr2) / ``sizeof``(arr2);``  ``relativeComplement(arr1, arr2, n, m);``  ``return` `0;``}`

## Java

 `// Java program to find all those``// elements of arr1[] that are not``// present in arr2[]` `class` `GFG``{``    ``static` `void` `relativeComplement(``int` `arr1[], ``int` `arr2[],``                                             ``int` `n, ``int` `m)``    ``{``    ` `        ``int` `i = ``0``, j = ``0``;``        ``while` `(i < n && j < m)``        ``{``        ` `            ``// If current element in arr2[] is``            ``// greater, then arr1[i] can't be``            ``// present in arr2[j..m-1]``            ``if` `(arr1[i] < arr2[j])``            ``{``                ``System.out.print(arr1[i] + ``" "``);``                ``i++;``        ` `            ``// Skipping smaller elements of``            ``// arr2[]``            ``} ``else` `if` `(arr1[i] > arr2[j])``            ``{``                ``j++;``        ` `            ``// Equal elements found (skipping``            ``// in both arrays)``            ``}``            ``else` `if` `(arr1[i] == arr2[j])``            ``{``                ``i++;``                ``j++;``            ``}``        ``}``        ` `        ``// Printing remaining elements of``        ``// arr1[]``        ``while` `(i < n)``            ``System.out.print(arr1[i] + ``" "``);``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `main (String[] args)``    ``{``        ``int` `arr1[] = {``3``, ``6``, ``10``, ``12``, ``15``};``        ``int` `arr2[] = {``1``, ``3``, ``5``, ``10``, ``16``};``        ``int` `n = arr1.length;``        ``int` `m = arr2.length;``        ``relativeComplement(arr1, arr2, n, m);``     ``}``}` `// This code is contributed by Anant Agarwal.`

## Python3

 `# Python program to find all those``# elements of arr1[] that are not``# present in arr2[]` `def` `relativeComplement(arr1, arr2, n, m):`` ` `    ``i ``=` `0``    ``j ``=` `0``    ``while` `(i < n ``and` `j < m):`` ` `        ``# If current element in arr2[] is``        ``# greater, then arr1[i] can't be``        ``# present in arr2[j..m-1]``        ``if` `(arr1[i] < arr2[j]):``            ``print``(arr1[i] , ``" "``, end``=``"")``            ``i ``+``=` `1`` ` `            ``# Skipping smaller elements of``            ``# arr2[]``        ``elif` `(arr1[i] > arr2[j]):``            ``j ``+``=` `1`` ` `            ``# Equal elements found (skipping``            ``# in both arrays)``        ``elif` `(arr1[i] ``=``=` `arr2[j]):``            ``i ``+``=` `1``            ``j ``+``=` `1``    ` `    ``# Printing remaining elements of``    ``# arr1[]``    ``while` `(i < n):``        ``print``(arr1[i] , ``" "``, end``=``"")`` ` `# Driver code``arr1``=` `[``3``, ``6``, ``10``, ``12``, ``15``]``arr2 ``=` `[``1``, ``3``, ``5``, ``10``, ``16``]``n ``=` `len``(arr1)``m ``=` `len``(arr2)``relativeComplement(arr1, arr2, n, m)` `# This code is contributed``# by Anant Agarwal.`

## C#

 `// C# program to find all those``// elements of arr1[] that are not``// present in arr2[]``using` `System;` `namespace` `Complement``{``    ``public` `class` `GFG``    ``{    ``                ` `        ``static` `void` `relativeComplement(``int` `[]arr1, ``int` `[]arr2,``                                                   ``int` `n, ``int` `m)``        ``{``    ` `        ``int` `i = 0, j = 0;``        ``while` `(i < n && j < m)``        ``{``        ` `            ``// If current element in arr2[] is``            ``// greater, then arr1[i] can't be``            ``// present in arr2[j..m-1]``            ``if` `(arr1[i] < arr2[j])``            ``{``                ``Console.Write(arr1[i] + ``" "``);``                ``i++;``        ` `            ``// Skipping smaller elements of``            ``// arr2[]``            ``} ``else` `if` `(arr1[i] > arr2[j])``            ``{``                ``j++;``        ` `            ``// Equal elements found (skipping``            ``// in both arrays)``            ``}``            ``else` `if` `(arr1[i] == arr2[j])``            ``{``                ``i++;``                ``j++;``            ``}``        ``}``        ` `        ``// Printing remaining elements of``        ``// arr1[]``        ``while` `(i < n)``            ``Console.Write(arr1[i] + ``" "``);``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``int` `[]arr1 = {3, 6, 10, 12, 15};``        ``int` `[]arr2 = {1, 3, 5, 10, 16};``        ``int` `n = arr1.Length;``        ``int` `m = arr2.Length;``        ``relativeComplement(arr1,arr2, n, m);``    ``}``    ``}``}` `// This code is contributed by Sam007`

## PHP

 ` ``\$arr2``[``\$j``])``        ``{``            ``\$j``++;``        ` `            ``// Equal elements found (skipping``            ``// in both arrays)``        ``}``        ``else` `if` `(``\$arr1``[``\$i``] == ``\$arr2``[``\$j``])``        ``{``            ``\$i``++;``            ``\$j``++;``        ``}``    ``}` `    ``// Printing remaining elements of``    ``// arr1[]``    ``while` `(``\$i` `< ``\$n``)``        ``echo` `\$arr1``[``\$i``] , ``" "``;``}` `// Driver code``{``    ``\$arr1` `= ``array``(3, 6, 10, 12, 15);``    ``\$arr2` `= ``array``(1, 3, 5, 10, 16);``    ``\$n` `= sizeof(``\$arr1``) / sizeof(``\$arr1``);``    ``\$m` `= sizeof(``\$arr2``) / sizeof(``\$arr2``);``    ``relativeComplement(``\$arr1``, ``\$arr2``, ``\$n``, ``\$m``);``    ``return` `0;``}` `// This code is contributed by nitin mittal``?>`

## Javascript

 ``

Output :

`6 12 15 `

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