Find minimum difference between any two elements

Difficulty Level : Basic
Last Updated : 20 Apr, 2021

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(n²)
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
?>

Javascript

<script>
 
    // Javascript 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
        arr.sort(function(a, b)
        {return a - b});
          
        // Initialize difference
        // as infinite
        let diff = Number.MAX_VALUE;
          
        // Find the min diff by
        // comparing adjacent pairs
        // in sorted array
        for (let i = 0; i < n - 1; i++)
            if (arr[i + 1] - arr[i] < diff)
                diff = arr[i + 1] - arr[i];
          
        // Return min diff
        return diff;
    }
     
    let arr = [1, 5, 3, 19, 18, 25];
    document.write("Minimum difference is "
    + findMinDiff(arr, arr.length));
     
</script>

Output :

Minimum difference is 1

Asked in: Amazon

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.

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