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# Longest sub-array whose product is 0

• Difficulty Level : Easy
• Last Updated : 26 Mar, 2021

Given an array arr[] of integer elements, the task is to find the length of the longest sub-array whose product is 0.
Examples:

Input: arr[] = {1, 2, 3, 0, 1, 2, 0}
Output:
{1, 2, 3, 0, 1, 2, 0} is the longest sub-array whose product is 0.
Input: arr[] = {1, 2, 3, 4, 5}
Output:
There is no sub-array possible whose product is 0.

Approach:

• If there is no element in the array which is equal to 0 then there will be no sub-array possible whose product is 0.
• If there is at least one element in the array which is equal to 0 then the longest sub-array whose product is 0 will be the complete array.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function to return the length of the``// longest sub-array whose product``// of elements is 0``int` `longestSubArray(``int` `arr[], ``int` `n)``{``    ``bool` `isZeroPresent = ``false``;``    ``for` `(``int` `i = 0; i < n; i++) {``        ``if` `(arr[i] == 0) {``            ``isZeroPresent = ``true``;``            ``break``;``        ``}``    ``}` `    ``if` `(isZeroPresent)``        ``return` `n;` `    ``return` `0;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 1, 2, 3, 0, 1, 2, 0 };``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr);``    ``cout << longestSubArray(arr, n);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GFG {` `    ``// Function to return the length of the``    ``// longest sub-array whose product``    ``// of elements is 0``    ``static` `int` `longestSubArray(``int` `arr[], ``int` `n)``    ``{``        ``boolean` `isZeroPresent = ``false``;``        ``for` `(``int` `i = ``0``; i < n; i++) {``            ``if` `(arr[i] == ``0``) {``                ``isZeroPresent = ``true``;``                ``break``;``            ``}``        ``}` `        ``if` `(isZeroPresent)``            ``return` `n;` `        ``return` `0``;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String args[])``    ``{``        ``int` `arr[] = { ``1``, ``2``, ``3``, ``0``, ``1``, ``2``, ``0` `};``        ``int` `n = arr.length;``        ``System.out.print(longestSubArray(arr, n));``    ``}``}`

## Python3

 `# Python3 implementation of the approach` `# Function to return the length of``# the longest sub-array whose product``# of elements is 0``def` `longestSubArray(arr, n) :` `    ``isZeroPresent ``=` `False``    ``for` `i ``in` `range` `(``0` `, n) :``        ``if` `(arr[i] ``=``=` `0``) :``            ``isZeroPresent ``=` `True``            ``break``        ` `    ``if` `(isZeroPresent) :``        ``return` `n` `    ``return` `0` `# Driver code``arr ``=` `[ ``1``, ``2``, ``3``, ``0``, ``1``, ``2``, ``0` `]``n ``=` `len``(arr)``print``(longestSubArray(arr, n))` `# This code is contributed by ihritik`

## C#

 `// C# implementation of the approach``using` `System;``class` `GFG {` `    ``// Function to return the length of the``    ``// longest sub-array whose product``    ``// of elements is 0``    ``static` `int` `longestSubArray(``int``[] arr, ``int` `n)``    ``{``        ``bool` `isZeroPresent = ``false``;``        ``for` `(``int` `i = 0; i < n; i++) {``            ``if` `(arr[i] == 0) {``                ``isZeroPresent = ``true``;``                ``break``;``            ``}``        ``}` `        ``if` `(isZeroPresent)``            ``return` `n;` `        ``return` `0;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``int``[] arr = { 1, 2, 3, 0, 1, 2, 0 };``        ``int` `n = arr.Length;``        ``Console.Write(longestSubArray(arr, n));``    ``}``}`

## PHP

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## Javascript

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Output:
`7`

Time Complexity: O(n)

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