# Shortest Un-ordered Subarray

• Difficulty Level : Easy
• Last Updated : 04 Aug, 2022

An array is given of n length, and problem is that we have to find the length of shortest unordered {neither increasing nor decreasing} sub array in given array.

Examples:

```Input : n = 5
7 9 10 8 11
Output : 3
Explanation : 9 10 8 unordered sub array.

Input : n = 5
1 2 3 4 5
Output : 0
Explanation :  Array is in increasing order.```

The idea is based on the fact that size of shortest subarray would be either 0 or 3. We have to check array element is either increasing or decreasing, if all array elements are in increasing or decreasing, then length of shortest sub array is 0, And if either the array element is not follow the increasing or decreasing then it shortest length is 3.

Implementation:

## C++

 `// CPP program to find shortest subarray which is``// unsorted.``#include ``using` `namespace` `std;` `// bool function for checking an array elements``// are in increasing.``bool` `increasing(``int` `a[], ``int` `n)``{``    ``for` `(``int` `i = 0; i < n - 1; i++)``        ``if` `(a[i] >= a[i + 1])``            ``return` `false``;   ``    ``return` `true``;``}` `// bool function for checking an array``// elements are in decreasing.``bool` `decreasing(``int` `a[], ``int` `n)``{``    ``for` `(``int` `i = 0; i < n - 1; i++)``        ``if` `(a[i] < a[i + 1])``            ``return` `false``;   ``    ``return` `true``;``}` `int` `shortestUnsorted(``int` `a[], ``int` `n)``{``    ``// increasing and decreasing are two functions.``    ``// if function return true value then print``    ``// 0 otherwise 3.``    ``if` `(increasing(a, n) == ``true` `||``       ``decreasing(a, n) == ``true``)``        ``return` `0;``    ``else``        ``return` `3;``}` `// Driver code``int` `main()``{``    ``int` `ar[] = { 7, 9, 10, 8, 11 };``    ``int` `n = ``sizeof``(ar) / ``sizeof``(ar[0]);``    ``cout << shortestUnsorted(ar, n);``    ``return` `0;``}`

## Java

 `// JAVA program to find shortest subarray which is``// unsorted.``import` `java.util.*;``import` `java.io.*;` `class` `GFG {``    ` `    ``// boolean function to check array elements``    ``// are in increasing order or not``    ``public` `static` `boolean` `increasing(``int` `a[],``int` `n)``    ``{``        ``for` `(``int` `i = ``0``; i < n - ``1``; i++)``            ``if` `(a[i] >= a[i + ``1``])``                ``return` `false``;``                ` `        ``return` `true``;``    ``}``    ` `    ``// boolean function to check array elements``    ``// are in decreasing order or not``    ``public` `static` `boolean` `decreasing(``int` `arr[],``int` `n)``    ``{``        ``for` `(``int` `i = ``0``; i < n - ``1``; i++)``            ``if` `(arr[i] < arr[i + ``1``])``                ``return` `false``;``                ` `        ``return` `true``;``    ``}``    ` `    ``public` `static` `int` `shortestUnsorted(``int` `a[],``int` `n)``    ``{``        ` `        ``// increasing and decreasing are two functions.``        ``// if function return true value then print``        ``// 0 otherwise 3.``        ``if` `(increasing(a, n) == ``true` `||``                             ``decreasing(a, n) == ``true``)``            ``return` `0``;``        ``else``            ``return` `3``;``    ``}``    ` `    ``// driver program``    ``public` `static` `void` `main (String[] args) {``        ` `        ``int` `ar[] = ``new` `int``[]{``7``, ``9``, ``10``, ``8``, ``11``};``        ``int` `n = ar.length;``        ` `        ``System.out.println(shortestUnsorted(ar,n));``    ``}``}` `// This code is contributed by Akash Singh.`

## Python3

 `# Python3 program to find shortest``# subarray which is unsorted` `# Bool function for checking an array ``# elements are in increasing``def` `increasing(a, n):` `    ``for` `i ``in` `range``(``0``, n ``-` `1``):``        ``if` `(a[i] >``=` `a[i ``+` `1``]):``            ``return` `False``            ` `    ``return` `True` `# Bool function for checking an array``# elements are in decreasing``def` `decreasing(a, n):` `    ``for` `i ``in` `range``(``0``, n ``-` `1``):``        ``if` `(a[i] < a[i ``+` `1``]):``            ``return` `False``            ` `    ``return` `True` `def` `shortestUnsorted(a, n):` `    ``# increasing and decreasing are two functions.``    ``# if function return True value then print``    ``# 0 otherwise 3.``    ``if` `(increasing(a, n) ``=``=` `True` `or``        ``decreasing(a, n) ``=``=` `True``):``        ``return` `0``    ``else``:``        ``return` `3` `# Driver code``ar ``=` `[``7``, ``9``, ``10``, ``8``, ``11``]``n ``=` `len``(ar)``print``(shortestUnsorted(ar, n))` `# This code is contributed by Smitha Dinesh Semwal.`

## C#

 `// Program to find the shortest``// subarray which is unsorted.``using` `System;` `class` `GFG {` `    ``// boolean function to check``    ``// array elements are in the``    ``// increasing order or not``    ``public` `static` `bool` `increasing(``int``[] a, ``int` `n)``    ``{``        ``for` `(``int` `i = 0; i < n - 1; i++)``            ``if` `(a[i] >= a[i + 1])``                ``return` `false``;` `        ``return` `true``;``    ``}` `    ``// boolean function to check``    ``// array elements are in the``    ``// decreasing order or not``    ``public` `static` `bool` `decreasing(``int``[] arr, ``int` `n)``    ``{``        ``for` `(``int` `i = 0; i < n - 1; i++)``            ``if` `(arr[i] < arr[i + 1])``                ``return` `false``;` `        ``return` `true``;``    ``}` `    ``public` `static` `int` `shortestUnsorted(``int``[] a, ``int` `n)``    ``{` `        ``// increasing and decreasing are``        ``// two functions. function return``        ``// true value then print 0 else 3``         ``if` `(increasing(a, n) == ``true` `||``             ``decreasing(a, n) == ``true``)``            ``return` `0;``        ``else``            ``return` `3;``    ``}` `    ``// Driver program``    ``public` `static` `void` `Main()``    ``{` `        ``int``[] ar = ``new` `int``[] { 7, 9, 10, 8, 11 };``        ``int` `n = ar.Length;``        ``Console.WriteLine(shortestUnsorted(ar, n));``    ``}``}` `// This code is contributed by vt_m.`

## PHP

 `= ``\$a``[``\$i` `+ 1])``            ``return` `false;``            ` `    ``return` `true;``}` `// bool function for checking an``// array elements are in decreasing.``function` `decreasing(``\$a``, ``\$n``)``{``    ``for` `(``\$i` `= 0; ``\$i` `< ``\$n` `- 1; ``\$i``++)``        ``if` `(``\$a``[``\$i``] < ``\$a``[``\$i` `+ 1])``            ``return` `false;``    ``return` `true;``}` `function` `shortestUnsorted(``\$a``, ``\$n``)``{``    ` `    ``// increasing and decreasing are``    ``// two functions. if function``    ``// return true value then print``    ``// 0 otherwise 3.``    ``if` `(increasing(``\$a``, ``\$n``) == true ||``          ``decreasing(``\$a``, ``\$n``) == true)``        ``return` `0;``    ``else``        ``return` `3;``}` `// Driver code``\$ar` `= ``array``( 7, 9, 10, 8, 11 );``\$n` `= sizeof(``\$ar``);``echo` `shortestUnsorted(``\$ar``, ``\$n``);` `// This code is contributed by``// nitin mittal.``?>`

## Javascript

 ``

Output :

`3`

Time complexity: O(n) where n is the length of the array.
Auxiliary Space: O(1)

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