Given an unsorted array, find the least difference between the element pairs. Display all the pairs present.

Problem Statement:

Given an unsorted array, list all the pairs with a least difference.

Example:

Input:

{5, 4, 3, 2, 1}

Output:

{1, 2}, {2, 3}, {3, 4}, {4, 5}.

Solution Explanation:

Step 1: Sort the array.
Step 2: Find the lest difference.
Step 3: Find all the pairs with that least difference.

First we take a for loop to find out the least difference. According to above example, it is 1.

After that we do following steps:

Pass 1:
Least_difference = 1;

Print {1, 2}

Pass 2:
Least_difference = 1;

Print {2, 3}

Pass 3:
Least_difference = 1;

Print {3, 4}

Pass 4:
Least_difference = 1;

Print {4, 5}

Solution in C:

#include<stdio.h>
#include <limits.h> // for INT_MAX


void print_array(int array[], int length)
{
	int index = 0;

	printf("The sorted array is \n");

	for(index = 0 ; index < length ; index++)
	{
		printf("%d\n",array[index] );
	}
}
void swap (int *num_1, int *num_2)
{
	int temp = *num_1;
	*num_1 = *num_2;
	*num_2 = temp;
}

void bubble_sort (int array[], int length)
{
	int outer_loop = 0;
	int inner_loop = 0;

	for(outer_loop = 0; outer_loop < length - 1; outer_loop ++)
	{
		for(inner_loop = 0; inner_loop < length - outer_loop - 1 ; inner_loop ++)
		{
			if(array [inner_loop] > array[inner_loop+1])
			{
				swap(&array[inner_loop], &array [inner_loop+1]);
			}
		}
	}
}


void getLeastDifferencePairs(int arr[], int lenght)
{
	int least_diff = INT_MAX;
	int itr = 0;

	int element_1 = 0;
	int element_2 = 0;

   for ( itr = 1; itr < lenght; itr++)
   {
      if (arr[itr] - arr[itr - 1] < least_diff)
      {
        least_diff = arr[itr] - arr[itr - 1];
      }
   }

   for (itr = 1; itr < lenght; ++itr) // start with 1, if not the result will be negative
   {
   		if(arr[itr] - arr[itr - 1] == least_diff)
   		{
   			printf("The least diff = %d, element 1 = %d, element 2 = %d\n", least_diff, arr[itr], arr[itr-1] );
   		}

   }

}

int main()
{
	int arr [100] = {5, 4, 3, 2, 1};
	int length = 5;


	bubble_sort(arr, length);
	getLeastDifferencePairs(arr, length);



}

Output:

The least diff = 1, element 1 = 2, element 2 = 1
The least diff = 1, element 1 = 3, element 2 = 2
The least diff = 1, element 1 = 4, element 2 = 3
The least diff = 1, element 1 = 5, element 2 = 4