# Maximum difference between two elements such that larger element appears after the smaller number in C

CServer Side ProgrammingProgramming

We are given with an array of integers of size N. The array consists of integers in random order. The task is to find the maximum difference between two elements such that the larger element appears after the smaller number. That is Arr[j]-Arr[i] is maximum such that j>i.

Input

Arr[] = { 2,1,3,8,3,19,21}.

Output −The maximum difference between two elements such that the larger element appears after the smaller number − 20

Explanation − The maximum difference is between 21 and 1 and 21 appears after 1 in the array.

Input

Arr[] = {18, 2,8,1,2,3,2,6 }.

Output −The maximum difference between two elements such that the larger element appears after the smaller number − 6

Explanation − The maximum difference is between 8 and 2 and 8 appears after 2 in the array.

## Approach used in the below program is as follows

• Declare an array of integers which contains pairs of sides of rectangle.( Arr[] )

• Create a variable to store the size of the array. (n)

• The function maxArea(int arr[],int n) is used to calculate the maximum area for rectangle. It takes an input array and its size as arguments.

• Inside maxArea() we declared an array Dim[2] two store highest two sides found after traversing the sorted array (in descending order) arr[].

• As arr[] is sorted in descending order the highest 4 sides must be in the beginning. We will iterate arr[] such that a pair of sides is found.

• Initialize Dim[] with 0 at first.

• Inside the while loop we put the condition that it continues till j<2 that there are no values found for dim[0] and dim[1] or the end of arr[] is reached. (i<n).

• If a pair of such sides is found, ( if(arr[i]==arr[i+1]) ), then store it in dim[j] and increment j for next side.

• Return the result as a product of dim[0] and dim[1].

• Note − sort(arr,n) is supposed to sort arr in descending order.

## Example

Live Demo

#include <stdio.h>
int maxDiff(int arr[], int n){
// Maximum difference found so far
int MD = arr[1] - arr[0];
// Minimum number visited so far
int min = arr[0];
for(int i = 1; i < n; i++){
if (arr[i] - min > MD)
MD = arr[i] - min;
if (arr[i] < min)
min = arr[i];
}
return MD;
}
/* Driver program to test above function */
int main(){
int arr[] = {2,5,7,3,4,12};
int n=6;
// Function calling
printf("Maximum difference is : %d ",maxDiff(arr, n));
return 0;
}

## Output

If we run the above code it will generate the following output −

The maximum difference between two elements such that the larger element appears after the smaller number : 10
Published on 14-Aug-2020 11:21:56