Given an unsorted array, find the minimum difference between any pair in given array.**Examples :**

Input : {1, 5, 3, 19, 18, 25}; Output : 1 Minimum difference is between 18 and 19 Input : {30, 5, 20, 9}; Output : 4 Minimum difference is between 5 and 9 Input : {1, 19, -4, 31, 38, 25, 100}; Output : 5 Minimum difference is between 1 and -4

**Method 1 (Simple: O(n ^{2})**

A simple solution is to use two loops.

## C++

`// C++ implementation of simple method to find` `// minimum difference between any pair` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Returns minimum difference between any pair` `int` `findMinDiff(` `int` `arr[], ` `int` `n)` `{` `// Initialize difference as infinite` `int` `diff = INT_MAX;` `// Find the min diff by comparing difference` `// of all possible pairs in given array` `for` `(` `int` `i=0; i<n-1; i++)` ` ` `for` `(` `int` `j=i+1; j<n; j++)` ` ` `if` `(` `abs` `(arr[i] - arr[j]) < diff)` ` ` `diff = ` `abs` `(arr[i] - arr[j]);` `// Return min diff` `return` `diff;` `}` `// Driver code` `int` `main()` `{` `int` `arr[] = {1, 5, 3, 19, 18, 25};` `int` `n = ` `sizeof` `(arr)/` `sizeof` `(arr[0]);` `cout << ` `"Minimum difference is "` `<< findMinDiff(arr, n);` `return` `0;` `}` |

## Java

`// Java implementation of simple method to find` `// minimum difference between any pair` `class` `GFG` `{` ` ` `// Returns minimum difference between any pair` ` ` `static` `int` `findMinDiff(` `int` `[] arr, ` `int` `n)` ` ` `{` ` ` `// Initialize difference as infinite` ` ` `int` `diff = Integer.MAX_VALUE;` ` ` ` ` `// Find the min diff by comparing difference` ` ` `// of all possible pairs in given array` ` ` `for` `(` `int` `i=` `0` `; i<n-` `1` `; i++)` ` ` `for` `(` `int` `j=i+` `1` `; j<n; j++)` ` ` `if` `(Math.abs((arr[i] - arr[j]) )< diff)` ` ` `diff = Math.abs((arr[i] - arr[j]));` ` ` ` ` `// Return min diff ` ` ` `return` `diff;` ` ` `}` ` ` `// Driver method to test the above function` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `arr[] = ` `new` `int` `[]{` `1` `, ` `5` `, ` `3` `, ` `19` `, ` `18` `, ` `25` `};` ` ` `System.out.println(` `"Minimum difference is "` `+` ` ` `findMinDiff(arr, arr.length));` ` ` ` ` `}` `}` |

## Python

`# Python implementation of simple method to find` `# minimum difference between any pair` `# Returns minimum difference between any pair` `def` `findMinDiff(arr, n):` ` ` `# Initialize difference as infinite` ` ` `diff ` `=` `10` `*` `*` `20` ` ` ` ` `# Find the min diff by comparing difference` ` ` `# of all possible pairs in given array` ` ` `for` `i ` `in` `range` `(n` `-` `1` `):` ` ` `for` `j ` `in` `range` `(i` `+` `1` `,n):` ` ` `if` `abs` `(arr[i]` `-` `arr[j]) < diff:` ` ` `diff ` `=` `abs` `(arr[i] ` `-` `arr[j])` ` ` `# Return min diff` ` ` `return` `diff` `# Driver code` `arr ` `=` `[` `1` `, ` `5` `, ` `3` `, ` `19` `, ` `18` `, ` `25` `]` `n ` `=` `len` `(arr)` `print` `(` `"Minimum difference is "` `+` `str` `(findMinDiff(arr, n)))` `# This code is contributed by Pratik Chhajer` |

## C#

`// C# implementation of simple method to find` `// minimum difference between any pair` `using` `System;` `class` `GFG {` ` ` ` ` `// Returns minimum difference between any pair` ` ` `static` `int` `findMinDiff(` `int` `[]arr, ` `int` `n)` ` ` `{` ` ` ` ` `// Initialize difference as infinite` ` ` `int` `diff = ` `int` `.MaxValue;` ` ` ` ` `// Find the min diff by comparing difference` ` ` `// of all possible pairs in given array` ` ` `for` `(` `int` `i = 0; i < n-1; i++)` ` ` `for` `(` `int` `j = i+1; j < n; j++)` ` ` `if` `(Math.Abs((arr[i] - arr[j]) ) < diff)` ` ` `diff = Math.Abs((arr[i] - arr[j]));` ` ` ` ` `// Return min diff` ` ` `return` `diff;` ` ` `}` ` ` `// Driver method to test the above function` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `[]arr = ` `new` `int` `[]{1, 5, 3, 19, 18, 25};` ` ` `Console.Write(` `"Minimum difference is "` `+` ` ` `findMinDiff(arr, arr.Length));` ` ` `}` `}` `// This code is contributed by nitin mittal.` |

## PHP

`<?php` `// PHP implementation of simple` `// method to find minimum` `// difference between any pair` `// Returns minimum difference` `// between any pair` `function` `findMinDiff(` `$arr` `, ` `$n` `)` `{` `// Initialize difference` `// as infinite` `$diff` `= PHP_INT_MAX;` `// Find the min diff by comparing` `// difference of all possible` `// pairs in given array` `for` `(` `$i` `= 0; ` `$i` `< ` `$n` `- 1; ` `$i` `++)` ` ` `for` `(` `$j` `= ` `$i` `+ 1; ` `$j` `< ` `$n` `; ` `$j` `++)` ` ` `if` `(` `abs` `(` `$arr` `[` `$i` `] - ` `$arr` `[` `$j` `]) < ` `$diff` `)` ` ` `$diff` `= ` `abs` `(` `$arr` `[` `$i` `] - ` `$arr` `[` `$j` `]);` `// Return min diff` `return` `$diff` `;` `}` `// Driver code` `$arr` `= ` `array` `(1, 5, 3, 19, 18, 25);` `$n` `= sizeof(` `$arr` `);` `echo` `"Minimum difference is "` `,` ` ` `findMinDiff(` `$arr` `, ` `$n` `);` `// This code is contributed by ajit` `?>` |

## Javascript

`<script>` `// JavaScript program implementation of simple method to find` `// minimum difference between any pair` ` ` `// Returns minimum difference between any pair` ` ` `function` `findMinDiff( arr, n)` ` ` `{` ` ` `// Initialize difference as infinite` ` ` `let diff = Number.MAX_VALUE;` ` ` ` ` `// Find the min diff by comparing difference` ` ` `// of all possible pairs in given array` ` ` `for` `(let i=0; i<n-1; i++)` ` ` `for` `(let j=i+1; j<n; j++)` ` ` `if` `(Math.abs((arr[i] - arr[j]) )< diff)` ` ` `diff = Math.abs((arr[i] - arr[j]));` ` ` ` ` `// Return min diff ` ` ` `return` `diff;` ` ` `}` `// Driver Code` ` ` `let arr = [1, 5, 3, 19, 18, 25];` ` ` `document.write(` `"Minimum difference is "` `+` ` ` `findMinDiff(arr, arr.length));` `</script>` |

**Output :**

Minimum difference is 1

**Method 2 (Efficient: O(n Log n)**

The idea is to use sorting. Below are steps.

1) Sort array in ascending order. This step takes O(n Log n) time.

2) Initialize difference as infinite. This step takes O(1) time.

3) Compare all adjacent pairs in sorted array and keep track of minimum difference. This step takes O(n) time.

Below is implementation of above idea.

## C++

`// C++ program to find minimum difference between` `// any pair in an unsorted array` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Returns minimum difference between any pair` `int` `findMinDiff(` `int` `arr[], ` `int` `n)` `{` ` ` `// Sort array in non-decreasing order` ` ` `sort(arr, arr+n);` ` ` `// Initialize difference as infinite` ` ` `int` `diff = INT_MAX;` ` ` `// Find the min diff by comparing adjacent` ` ` `// pairs in sorted array` ` ` `for` `(` `int` `i=0; i<n-1; i++)` ` ` `if` `(arr[i+1] - arr[i] < diff)` ` ` `diff = arr[i+1] - arr[i];` ` ` `// Return min diff` ` ` `return` `diff;` `}` `// Driver code` `int` `main()` `{` ` ` `int` `arr[] = {1, 5, 3, 19, 18, 25};` ` ` `int` `n = ` `sizeof` `(arr)/` `sizeof` `(arr[0]);` ` ` `cout << ` `"Minimum difference is "` `<< findMinDiff(arr, n);` ` ` `return` `0;` `}` |

## Java

`// Java program to find minimum difference between` `// any pair in an unsorted array` `import` `java.util.Arrays;` `class` `GFG` `{` ` ` `// Returns minimum difference between any pair` ` ` `static` `int` `findMinDiff(` `int` `[] arr, ` `int` `n)` ` ` `{` ` ` `// Sort array in non-decreasing order` ` ` `Arrays.sort(arr);` ` ` ` ` `// Initialize difference as infinite` ` ` `int` `diff = Integer.MAX_VALUE;` ` ` ` ` `// Find the min diff by comparing adjacent` ` ` `// pairs in sorted array` ` ` `for` `(` `int` `i=` `0` `; i<n-` `1` `; i++)` ` ` `if` `(arr[i+` `1` `] - arr[i] < diff)` ` ` `diff = arr[i+` `1` `] - arr[i];` ` ` ` ` `// Return min diff` ` ` `return` `diff;` ` ` `}` ` ` `// Driver method to test the above function` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `arr[] = ` `new` `int` `[]{` `1` `, ` `5` `, ` `3` `, ` `19` `, ` `18` `, ` `25` `};` ` ` `System.out.println(` `"Minimum difference is "` `+` ` ` `findMinDiff(arr, arr.length));` ` ` ` ` `}` `}` |

## Python

`# Python program to find minimum difference between` `# any pair in an unsorted array` `# Returns minimum difference between any pair` `def` `findMinDiff(arr, n):` ` ` `# Sort array in non-decreasing order` ` ` `arr ` `=` `sorted` `(arr)` ` ` `# Initialize difference as infinite` ` ` `diff ` `=` `10` `*` `*` `20` ` ` `# Find the min diff by comparing adjacent` ` ` `# pairs in sorted array` ` ` `for` `i ` `in` `range` `(n` `-` `1` `):` ` ` `if` `arr[i` `+` `1` `] ` `-` `arr[i] < diff:` ` ` `diff ` `=` `arr[i` `+` `1` `] ` `-` `arr[i]` ` ` `# Return min diff` ` ` `return` `diff` `# Driver code` `arr ` `=` `[` `1` `, ` `5` `, ` `3` `, ` `19` `, ` `18` `, ` `25` `]` `n ` `=` `len` `(arr)` `print` `(` `"Minimum difference is "` `+` `str` `(findMinDiff(arr, n)))` `# This code is contributed by Pratik Chhajer` |

## C#

`// C# program to find minimum` `// difference between any pair` `// in an unsorted array` `using` `System;` `class` `GFG` `{` ` ` `// Returns minimum difference` ` ` `// between any pair` ` ` `static` `int` `findMinDiff(` `int` `[] arr,` ` ` `int` `n)` ` ` `{` ` ` `// Sort array in` ` ` `// non-decreasing order` ` ` `Array.Sort(arr);` ` ` ` ` `// Initialize difference` ` ` `// as infinite` ` ` `int` `diff = ` `int` `.MaxValue;` ` ` ` ` `// Find the min diff by` ` ` `// comparing adjacent pairs` ` ` `// in sorted array` ` ` `for` `(` `int` `i = 0; i < n - 1; i++)` ` ` `if` `(arr[i + 1] - arr[i] < diff)` ` ` `diff = arr[i + 1] - arr[i];` ` ` ` ` `// Return min diff` ` ` `return` `diff;` ` ` `}` ` ` `// Driver Code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `[]arr = ` `new` `int` `[]{1, 5, 3, 19, 18, 25};` ` ` `Console.WriteLine(` `"Minimum difference is "` `+` ` ` `findMinDiff(arr, arr.Length));` ` ` ` ` `}` `}` `//This code is contributed by anuj_67.` |

## PHP

`<?php` `// PHP program to find minimum` `// difference between any pair` `// in an unsorted array` `// Returns minimum difference` `// between any pair` `function` `findMinDiff(` `$arr` `, ` `$n` `)` `{` ` ` `// Sort array in` `// non-decreasing order` `sort(` `$arr` `);` `// Initialize difference` `// as infinite` `$diff` `= PHP_INT_MAX;` `// Find the min diff by` `// comparing adjacent` `// pairs in sorted array` `for` `(` `$i` `= 0; ` `$i` `< ` `$n` `- 1; ` `$i` `++)` ` ` `if` `(` `$arr` `[` `$i` `+ 1] - ` `$arr` `[` `$i` `] < ` `$diff` `)` ` ` `$diff` `= ` `$arr` `[` `$i` `+ 1] - ` `$arr` `[` `$i` `];` `// Return min diff` `return` `$diff` `;` `}` `// Driver code` `$arr` `= ` `array` `(1, 5, 3, 19, 18, 25);` `$n` `= sizeof(` `$arr` `);` `echo` `"Minimum difference is "` `,` ` ` `findMinDiff(` `$arr` `, ` `$n` `);` `// This code is contributed ajit` `?>` |

**Output :**

Minimum difference is 1

This article is contributed by **Harshit Agrawal**. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the **DSA Self Paced Course** at a student-friendly price and become industry ready.