Find minimum difference between any two elements (pair) in given array

// 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 code
    public static void Main()
    {
        int[] arr = new int[] { 1, 5, 3, 19, 18, 25 };

        // Function call
        Console.Write("Minimum difference is "
                      + findMinDiff(arr, arr.Length));
    }
}

// This code is contributed by nitin mittal.

// 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 };

        // Function call
        Console.WriteLine("Minimum difference is "
                          + findMinDiff(arr, arr.Length));
    }
}

// This code is contributed by anuj_67.

using System;
using System.Collections.Generic;

class Program
{
    static int FindMinDiff(int[] arr)
    {
        Dictionary<int, int> dict = new Dictionary<int, int>();
        int minDiff = int.MaxValue;

        for (int i = 0; i < arr.Length; i++)
        {
            // Find the first element that is greater than or equal to arr[i]
            KeyValuePair<int, int>? greaterOrEqual = null;

            foreach (var kvp in dict)
            {
                if (kvp.Key >= arr[i])
                {
                    greaterOrEqual = kvp;
                    break;
                }
            }

            if (greaterOrEqual != null)
            {
                // Check difference between the current element 
                //and the next element in the dictionary
                minDiff = Math.Min(minDiff, greaterOrEqual.Value.Key - arr[i]);
            }

            // Find the previous element in the dictionary
            KeyValuePair<int, int>? previous = null;

            foreach (var kvp in dict)
            {
                if (kvp.Key < arr[i])
                {
                    previous = kvp;
                }
                else
                {
                    break;
                }
            }

            if (previous != null)
            {
                // Check difference between the current 
                // element and the previous element in the dictionary
                minDiff = Math.Min(minDiff, arr[i] - previous.Value.Key);
            }

            // Insert the current element into the dictionary
            dict[arr[i]] = i;
        }

        return minDiff;
    }

    static void Main()
    {
        int[] arr = { 1, 5, 3, 19, 18, 25 };
        int minDiff = FindMinDiff(arr);
        Console.WriteLine(minDiff);
    }
}

using System;

public class GFG {

    static public void Main()
    {

        // Code
        int[] arr = new int[] { 1, 5, 3, 19, 18, 25 };

        // Function call
        var sln = new Solution();
        var minDiff
            = sln.MinimumDifference(arr, arr.Length);
        Console.WriteLine("Minimum difference is "
                          + minDiff);
    }
}
class Solution {
    // Function to find minimum difference between any pair
    // of elements in an array.
    public int MinimumDifference(int[] arr, int n)
    {
        // code here
        if (arr.Length < 2)
            return int.MaxValue;
        int mid = arr.Length / 2;
        int[] left = new int[mid];
        int[] right = new int[arr.Length - mid];
        int i = 0;
        while (i < mid) {
            left[i] = arr[i];
            i += 1;
        }
        while (i < arr.Length) {
            right[i - mid] = arr[i];
            i += 1;
        }
        var ls = MinimumDifference(left, left.Length);
        var rs = MinimumDifference(right, right.Length);
        var mg = mergeHelper(left, right, arr);
        return Math.Min(mg, Math.Min(ls, rs));
    }
    private int mergeHelper(int[] left, int[] right,
                            int[] arr)
    {
        int i = 0;
        int j = 0;
        int k = 0;
        int minDiff = int.MaxValue;
        while (i < left.Length && j < right.Length) {
            if (left[i] <= right[j]) {
                minDiff
                    = Math.Min(minDiff, right[j] - left[i]);
                arr[k] = left[i];
                i += 1;
            }
            else {
                minDiff
                    = Math.Min(minDiff, left[i] - right[j]);
                arr[k] = right[j];
                j += 1;
            }
            k += 1;
        }
        while (i < left.Length) {
            arr[k] = left[i];
            i += 1;
            k += 1;
        }
        while (j < right.Length) {
            arr[k] = right[j];
            j += 1;
            k += 1;
        }
        return minDiff;
    }
}