Maximum and minimum of an array using minimum number of comparisons in C

We are given with an array of integers. The task is to find the minimum and maximum element of the array in the minimum number of comparisons.

Input 

Arr[] = { 1,2,4,5,-3,91 }

Output 

Maximum element : 91 Minimum Element : -3

Explanation − Here to minimize the number of comparisons, we will initialize the maximum and minimum element with Arr[0]. And starting from the 2nd element compare each value with min and max and update accordingly.

Input 

Arr[] = { 10,20,21,31,18,11 }

Output 

Maximum element : 31 Minimum Element : 10

Explanation − Here also, to minimize the number of comparisons, we will initialize the maximum and minimum element with Arr[0]. And starting from the 2nd element compare each value with min and max and update accordingly.

Approach used in the below program is as follows

• We take an integer array having numbers as Arr[]

• The function getresult( int arr[],int n) is to find the maximum and minimum element present in the array in minimum no. of comparisons.

• If there is only one element then we will initialize the variables max and min with arr[0] .

• For more than one element, we will initialize max with arr[1] and min with arr[0].

• Inside for loop start traversing from third element ( i=2 ) till last.

• Now we will compare each value ( arr[i] ) with min and max. If it is less than min, update min with arr[i]. If it is more than max, then update max with arr[i].

• In the end print the results stored in max and min variables.

Example

 Live Demo

#include <stdio.h>
#include <math.h>
int getresult(int arr[], int n){
   int min=0,max=0;
   /*If there is only one element then return it as min and max both*/
   if (n == 1)
      { min=max=arr[0]; }
   /* If there are more than one elements, then initialize min and max*/
   if (arr[0] > arr[1]){
      max = arr[0];
      min = arr[1];
   }
   else{
      max = arr[1];
      min = arr[0];
   }
   for (int i = 2; i<n; i++){
      if (arr[i] > max)
         max = arr[i];
      else if (arr[i] < min)
         min = arr[i];
   }
   printf(" Minimum element: %d", min);
   printf(" Maximum element: %d", max);
}
/* Driver program to test above function */
int main(){
   int arr[] = {200, 191, 112, -11, 330, 60};
   int n = 6;
   getresult (arr, n);
}

Output

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

Minimum element: -11 Maximum element: 330