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 / 4Input: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 <bits/stdc++.h>` `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[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` `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[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))` ` ` `Console.WriteLine(` `"Yes"` `);` ` ` `else` ` ` `Console.WriteLine(` `"No"` `);` `}` `}` `// This code is contributed by Princi Singh` |

## Javascript

`<script>` `// Javascript implementation of the approach` `// Function that returns true if the` `// given four integers are in proportion` `function` `inProportion(arr)` `{` ` ` `// Array will consist of` ` ` `// only four integers` ` ` `var` `n = 4;` ` ` `// Sort the array` ` ` `arr.sort();` ` ` `// Find the product of extremes and means` ` ` `var` `extremes = arr[0] * arr[3];` ` ` `var` `means = arr[1] * arr[2];` ` ` `// If the products are equal` ` ` `if` `(extremes == means)` ` ` `return` `true` `;` ` ` `return` `false` `;` `}` `// Driver code` `var` `arr = [ 1, 2, 4, 2 ]` `if` `(inProportion(arr))` ` ` `document.write(` `"Yes"` `);` `else` ` ` `document.write(` `"No"` `);` `// This code is contributed by rutvik_56.` `</script>` |

**Output:**

Yes

**Time Complexity:** O(1)

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