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# Check whether the given integers a, b, c and d are in proportion

• Last Updated : 01 Apr, 2021

Given four integers a, b, c and d. The task is to check whether it is possible to pair them up such that they are in proportion. We are allowed to shuffle the order of the numbers.
Examples:

Input: arr[] = {1, 2, 4, 2}
Output: Yes
1 / 2 = 2 / 4
Input: arr[] = {1, 2, 5, 2}
Output: No

Approach: If four numbers a, b, c and d are in proportion then a:b = c:d. The solution is to sort the four numbers and pair up the first 2 together and the last 2 together and check their ratios this is because, in order for them to be in proportion, the product of means has to be equal to the product of extremes. So, a * d has to be equal to c * b.
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function that returns true if the``// given four integers are in proportion``bool` `inProportion(``int` `arr[])``{` `    ``// Array will consist of``    ``// only four integers``    ``int` `n = 4;` `    ``// Sort the array``    ``sort(arr, arr + n);` `    ``// Find the product of extremes and means``    ``long` `extremes = (``long``)arr * (``long``)arr;``    ``long` `means = (``long``)arr * (``long``)arr;` `    ``// If the products are equal``    ``if` `(extremes == means)``        ``return` `true``;``    ``return` `false``;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 1, 2, 4, 2 };` `    ``if` `(inProportion(arr))``        ``cout << ``"Yes"``;``    ``else``        ``cout << ``"No"``;` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``import` `java.util.*;` `class` `GFG``{``    ` `// Function that returns true if the``// given four integers are in proportion``static` `boolean` `inProportion(``int` `[]arr)``{` `    ``// Array will consist of``    ``// only four integers``    ``int` `n = ``4``;` `    ``// Sort the array``    ``Arrays.sort(arr);` `    ``// Find the product of extremes and means``    ``long` `extremes = (``long``)arr[``0``] * (``long``)arr[``3``];``    ``long` `means = (``long``)arr[``1``] * (``long``)arr[``2``];` `    ``// If the products are equal``    ``if` `(extremes == means)``        ``return` `true``;``    ``return` `false``;``}` `// Driver code``public` `static` `void` `main(String args[])``{``    ``int` `arr[] = { ``1``, ``2``, ``4``, ``2` `};` `    ``if` `(inProportion(arr))``        ``System.out.println(``"Yes"``);``    ``else``        ``System.out.println(``"No"``);``}``}` `// This code is contributed by Rajput-Ji`

## Python3

 `# Python3 implementation of the approach` `# Function that returns true if the``# given four integers are in proportion``def` `inProportion(arr) :` `    ``# Array will consist of``    ``# only four integers``    ``n ``=` `4``;` `    ``# Sort the array``    ``arr.sort()` `    ``# Find the product of extremes and means``    ``extremes ``=` `arr[``0``] ``*` `arr[``3``];``    ``means ``=` `arr[``1``] ``*` `arr[``2``];` `    ``# If the products are equal``    ``if` `(extremes ``=``=` `means) :``        ``return` `True``;``        ` `    ``return` `False``;` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:` `    ``arr ``=` `[ ``1``, ``2``, ``4``, ``2` `];` `    ``if` `(inProportion(arr)) :``        ``print``(``"Yes"``);``    ``else` `:``        ``print``(``"No"``);` `# This code is contributed by AnkitRai01`

## C#

 `// C# implementation of the approach``using` `System;``                    ` `class` `GFG``{``    ` `// Function that returns true if the``// given four integers are in proportion``static` `bool` `inProportion(``int` `[]arr)``{` `    ``// Array will consist of``    ``// only four integers``    ``int` `n = 4;` `    ``// Sort the array``    ``Array.Sort(arr);` `    ``// Find the product of extremes and means``    ``long` `extremes = (``long``)arr * (``long``)arr;``    ``long` `means = (``long``)arr * (``long``)arr;` `    ``// If the products are equal``    ``if` `(extremes == means)``        ``return` `true``;``    ``return` `false``;``}` `// Driver code``public` `static` `void` `Main(String []args)``{``    ``int` `[]arr = { 1, 2, 4, 2 };` `    ``if` `(inProportion(arr))``        ``Console.WriteLine(``"Yes"``);``    ``else``        ``Console.WriteLine(``"No"``);``}``}` `// This code is contributed by Princi Singh`

## Javascript

 ``
Output:

`Yes`

Time Complexity: O(1)

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