# Greatest contiguous sub-array of size K

• Difficulty Level : Medium
• Last Updated : 02 Jun, 2021

Given an array arr[] of integers and an integer K, the task is to find the greatest contiguous sub-array of size K. Sub-array X is said to be greater than sub-array Y if the first non-matching element in both the sub-arrays has a greater value in X than in Y.

Examples:

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Input: arr[] = {1, 4, 3, 2, 5}, K = 4
Output: 4 3 2 5
Two subarrays are {1, 4, 3, 2} and {4, 3, 2, 5}.
Hence, the greater one is {4, 3, 2, 5}

Input: arr[] = {1, 9, 2, 7, 9, 3}, K = 3
Output: 9 2 7

Approach: Generate all the sub-arrays of size K and store them in any Data-Structure. Sort all the sub-arrays, and the answer will be the last sub-array in the sorted Data-structure. In C++, we can use a vector of vectors to store sub-arrays of size K

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function that returns the sub-array``vector<``int``> findSubarray(``int` `a[], ``int` `k, ``int` `n)``{` `    ``// Data-structure to store all``    ``// the sub-arrays of size K``    ``vector > vec;` `    ``// Iterate to find all the sub-arrays``    ``for` `(``int` `i = 0; i < n - k + 1; i++) {``        ``vector<``int``> temp;` `        ``// Store the sub-array elements in the array``        ``for` `(``int` `j = i; j < i + k; j++) {``            ``temp.push_back(a[j]);``        ``}` `        ``// Push the vector in the container``        ``vec.push_back(temp);``    ``}` `    ``// Sort the vector of elements``    ``sort(vec.begin(), vec.end());` `    ``// The last sub-array in the sorted order``    ``// will be the answer``    ``return` `vec[vec.size() - 1];``}` `// Driver code``int` `main()``{``    ``int` `a[] = { 1, 4, 3, 2, 5 };``    ``int` `k = 4;``    ``int` `n = ``sizeof``(a) / ``sizeof``(a[0]);` `    ``// Get the sub-array``    ``vector<``int``> ans = findSubarray(a, k, n);` `    ``for` `(``auto` `it : ans)``        ``cout << it << ``" "``;``}`

## Java

 `// Java implementation of the approach``import` `java.io.*;``import` `java.util.*;` `class` `GFG{``    ` `// Function that returns the sub-array``static` `ArrayList findSubarray(``int` `a[],``                                       ``int` `k, ``int` `n)``{``    ` `    ``// Data-structure to store all``    ``// the sub-arrays of size K``    ``ArrayList<``    ``ArrayList> vec = ``new` `ArrayList<``                                  ``ArrayList>();``                                  ` `    ``// Iterate to find all the sub-arrays``    ``for``(``int` `i = ``0``; i < n - k + ``1``; i++)``    ``{``        ``ArrayList temp = ``new` `ArrayList();``        ` `        ``// Store the sub-array elements in the array``        ``for``(``int` `j = i; j < i + k; j++)``        ``{``            ``temp.add(a[j]);``        ``}``        ` `        ``// Push the vector in the container``        ``vec.add(temp);``    ``}``    ` `     ``// Sort the vector of elements``    ``Collections.sort(vec, ``new` `Comparator>()``    ``{   ``        ``@Override``        ``public` `int` `compare(ArrayList o1,``                           ``ArrayList o2)``        ``{``            ``return` `o1.get(``0``).compareTo(o2.get(``0``));``        ``}              ``    ``});``    ` `    ``// The last sub-array in the sorted order``    ``// will be the answer``    ``return` `vec.get(vec.size() - ``1``);``}` `// Driver code``public` `static` `void` `main(String[] args)``{``    ``int` `a[] = { ``1``, ``4``, ``3``, ``2``, ``5` `};``    ``int` `k = ``4``;``    ``int` `n = a.length;``    ` `    ``// Get the sub-array``    ``ArrayList ans = findSubarray(a, k, n);``    ` `    ``for``(``int` `it: ans)``    ``{``        ``System.out.print(it + ``" "``);``    ``}``}``}` `// This code is contributed by avanitrachhadiya2155`

## Python3

 `# Python3 implementation of the approach` `# Function that returns the sub-array``def` `findSubarray(a, k, n):` `    ``# Data-structure to store all``    ``# the sub-arrays of size K``    ``vec``=``[]` `    ``# Iterate to find all the sub-arrays``    ``for` `i ``in` `range``(n``-``k``+``1``):``        ``temp``=``[]` `        ``# Store the sub-array elements in the array``        ``for` `j ``in` `range``(i,i``+``k):``            ``temp.append(a[j])` `        ``# Push the vector in the container``        ``vec.append(temp)` `    ``# Sort the vector of elements``    ``vec``=``sorted``(vec)` `    ``# The last sub-array in the sorted order``    ``# will be the answer``    ``return` `vec[``len``(vec) ``-` `1``]` `# Driver code` `a ``=``[ ``1``, ``4``, ``3``, ``2``, ``5` `]``k ``=` `4``n ``=` `len``(a)` `# Get the sub-array``ans ``=` `findSubarray(a, k, n)` `for` `it ``in` `ans:``    ``print``(it,end``=``" "``)``    ` `# This code is contributed by mohit kumar 29`

## C#

 `// C# implementation of the approach``using` `System;``using` `System.Collections.Generic;``using` `System.Linq;` `public` `class` `GFG``{` `  ``// Function that returns the sub-array``  ``static` `List<``int``> findSubarray(``int``[] a, ``int` `k, ``int` `n)``  ``{``    ``// Data-structure to store all``    ``// the sub-arrays of size K``    ``List> vec = ``new` `List>();` `    ``// Iterate to find all the sub-arrays``    ``for``(``int` `i = 0; i < n - k + 1; i++)``    ``{``      ``List<``int``> temp = ``new` `List<``int``>();` `      ``// Store the sub-array elements in the array``      ``for``(``int` `j = i; j < i + k; j++)``      ``{``        ``temp.Add(a[j]);``      ``}` `      ``// Push the vector in the container``      ``vec.Add(temp);``    ``}` `    ``// Sort the vector of elements``    ``vec.OrderBy( l => l[0]);` `    ``// The last sub-array in the sorted order``    ``// will be the answer``    ``return` `vec[vec.Count - 1];``  ``}` `  ``// Driver code``  ``static` `public` `void` `Main (){``    ``int``[] a = { 1, 4, 3, 2, 5 };``    ``int` `k = 4;``    ``int` `n = a.Length;` `    ``// Get the sub-array``    ``List<``int``> ans = findSubarray(a, k, n);``    ``foreach``(``int` `it ``in` `ans)``    ``{``      ``Console.Write(it + ``" "``);``    ``}``  ``}``}` `// This code is contributed by rag2127`

## Javascript

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Output:
`4 3 2 5`

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