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++

// 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

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

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.