# Length of longest sub-array with maximum arithmetic mean.

• Last Updated : 31 May, 2022

Given an array of n-elements find the longest sub-array with the greatest arithmetic mean. The length of the sub-array must be greater than 1 and the mean should be calculated as an integer only.
Examples:

```Input : arr[] = {3, 2, 1, 2}
Output : 2
sub-array 3, 2 has greatest arithmetic mean

Input :arr[] = {3, 3, 3, 2}
Output : 3```

The idea is to first find the greatest mean of two consecutive elements from the array. Again iterate over the array and try to find the longest sequence in which each element must be greater or equal to the greatest mean calculated.
Above approach works because of these key points:

• Minimum possible sequence length is 2 and hence the greatest mean of two consecutive elements will always be part of the result.
• Any element which is equal or greater than the calculated mean may be the part of the longest sequence.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the above approach``#include ``using` `namespace` `std;` `// Function to find maximum distance``// between unequal elements``int` `longestSubarray(``int` `arr[], ``int` `n)``{` `    ``// Calculate maxMean``    ``int` `maxMean = 0;``    ``for` `(``int` `i = 1; i < n; i++)``        ``maxMean = max(maxMean,``                      ``(arr[i] + arr[i - 1]) / 2);` `    ``// Iterate over array and calculate largest subarray``    ``// with all elements greater or equal to maxMean``    ``int` `ans = 0;``    ``int` `subarrayLength = 0;``    ``for` `(``int` `i = 0; i < n; i++)``        ``if` `(arr[i] >= maxMean)``            ``ans = max(ans, ++subarrayLength);``        ``else``            ``subarrayLength = 0;` `    ``return` `ans;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 4, 3, 3, 2, 1, 4 };` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr);` `    ``cout << longestSubarray(arr, n);` `    ``return` `0;``}`

## Java

 `// Java implementation of the above approach``import` `java.io.*;` `class` `GFG``{``    ` `// Function to find maximum distance``// between unequal elements``static` `int` `longestSubarray(``int` `arr[], ``int` `n)``{` `    ``// Calculate maxMean``    ``int` `maxMean = ``0``;``    ``for` `(``int` `i = ``1``; i < n; i++)``        ``maxMean = Math.max(maxMean,``                    ``(arr[i] + arr[i - ``1``]) / ``2``);` `    ``// Iterate over array and calculate largest subarray``    ``// with all elements greater or equal to maxMean``    ``int` `ans = ``0``;``    ``int` `subarrayLength = ``0``;``    ``for` `(``int` `i = ``0``; i < n; i++)``        ``if` `(arr[i] >= maxMean)``            ``ans = Math.max(ans, ++subarrayLength);``        ``else``            ``subarrayLength = ``0``;` `    ``return` `ans;``}` `// Driver code``public` `static` `void` `main (String[] args)``{` `    ``int` `arr[] = { ``4``, ``3``, ``3``, ``2``, ``1``, ``4` `};``    ``int` `n = arr.length;``    ``System.out.println (longestSubarray(arr, n));``}``}` `// This code is contributed by ajit_00023`

## Python3

 `    ` `# Python implementation of the above approach` `# Function to find maximum distance``# between unequal elements``def` `longestSubarray(arr, n):` `    ``# Calculate maxMean``    ``maxMean ``=` `0``;``    ``for` `i ``in` `range``(``1``, n):``        ``maxMean ``=` `max``(maxMean,``                    ``(arr[i] ``+` `arr[i ``-` `1``]) ``/``/` `2``);` `    ``# Iterate over array and calculate largest subarray``    ``# with all elements greater or equal to maxMean``    ``ans ``=` `0``;``    ``subarrayLength ``=` `0``;``    ``for` `i ``in` `range``(n):``        ``if` `(arr[i] >``=` `maxMean):``            ``subarrayLength ``+``=` `1``;``            ``ans ``=` `max``(ans, subarrayLength);``        ``else``:``            ``subarrayLength ``=` `0``;` `    ``return` `ans;` `# Driver code``arr ``=` `[ ``4``, ``3``, ``3``, ``2``, ``1``, ``4` `];` `n ``=` `len``(arr);` `print``(longestSubarray(arr, n));` `# This code contributed by PrinciRaj1992`

## C#

 `// C# program for the above approach``using` `System;` `class` `GFG``{``    ` `    ``// Function to find maximum distance``    ``// between unequal elements``    ``static` `int` `longestSubarray(``int` `[]arr,``                               ``int` `n)``    ``{``    ` `        ``// Calculate maxMean``        ``int` `maxMean = 0;``        ``for` `(``int` `i = 1; i < n; i++)``            ``maxMean = Math.Max(maxMean,``                              ``(arr[i] + arr[i - 1]) / 2);``    ` `        ``// Iterate over array and calculate``        ``// largest subarray with all elements``        ``// greater or equal to maxMean``        ``int` `ans = 0;``        ``int` `subarrayLength = 0;``        ``for` `(``int` `i = 0; i < n; i++)``            ``if` `(arr[i] >= maxMean)``                ``ans = Math.Max(ans, ++subarrayLength);``            ``else``                ``subarrayLength = 0;``    ` `        ``return` `ans;``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `Main ()``    ``{``    ` `        ``int` `[]arr = { 4, 3, 3, 2, 1, 4 };``        ``int` `n = arr.Length;``        ``Console.WriteLine(longestSubarray(arr, n));``    ``}``}` `// This code is contributed by AnkitRai01`

## Javascript

 ``

Output:

`3`

Time Complexity : O(N)

Auxiliary Space: O(1)

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