How to find the minimum and maximum element of an Array in C++?

How to find the minimum and maximum element of an Array using STL in C++?
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How to find the minimum and maximum element of an Array in C++?

In this article, you’ll be learning how you can find the minimum and maximum element of an Array using STL in C++

Given an array arr[], find the minimum and maximum element of this array using STL in C++.
Example:

Input: 1, 11, 2, 4, 19, 22, 34, 56, 71, 23, 2, 0, 53

Output: min = 0, max = 71

Approach 1: Linear Comparisons 

  • Consider the first element as the minimum and maximum 
  • From the second element onwards compare each element with the minimum and maximum.
  • If the element is less than the minimum, then make it as the new minimum.
  • If the element is greater than the maximum, then make it as the new maximum.
  • Number of comparisons in worst case: 2(n-1)

  
 #include<bits/stdc++.h>
  
 using namespace std;
  
 class MinMax
 {
     public:
  
     // Method to find min and max elements of an array using 
     // Linear comparing
     vector<int> minMaxLinearCompare(vector<int> &arr, int size)
     {
         // 0th index: minimum
         // 1st index: maximum
         int max_index    =  1;
         int min_index    =  0;
         vector<int> minmax;
  
         // input array is empty 
         if(size == 0) return minmax;
         
         minmax.push_back(arr[0]);
         minmax.push_back(arr[0]);
  
         // comparing each element with min and max 
         for(int i=1; i<size; i++)
         {
             if(arr[i] > minmax[max_index]) 
                 minmax[max_index] = arr[i];
             else if(arr[i] < minmax[min_index])
                 minmax[min_index] = arr[i];
                 
         }
         return minmax;
  
     }
  
     
 };
  
  
 int main()
 {
     //creating the ReverseAray object
     MinMax mnmx;
     vector<int> arr = {1,11,2,4,19,22,34,56,71,23,2,0,53};
     int arr_size = arr.size();
     vector<int> mnmax;
     mnmax = mnmx.minMaxLinearCompare(arr, arr_size);
     if(mnmax.size() > 0)
     {
         cout<<"min "<<mnmax[0]<<" max "<<mnmax[1]<<endl;
     }
     return 0;
 }
  
  
  
   

Approach 2: Pair-wise Comparisons

  • If the size of array is odd, then assign first element as minimum and maximum
  • If the size of array is even, then compare the first two elements, make the larger element as maximum and smaller element as minimum.
  • From the third element onwards consider two elements at a time and compare them, then compare the lager element with maximum and smaller one with the minimum.
  • Number of comparisons in worst case: 3/2(n-1) + 1
 
 #include<bits/stdc++.h>
  
 using namespace std;
  
 class MinMax
 {
     public:
  
     // Method to find min and max elements of an array using 
     // comparison in pairs
     vector<int> minMaxPairCompare(vector<int> &arr, int size)
     {
         // 0th index: minimum
         // 1st index: maximum
         int max_index    =  1;
         int min_index    =  0;
         int begin_index  = -1;
         vector<int> minmax;
  
         // input array is empty 
         if(size == 0) return minmax;
         
         // input array contains only one element
         if(size == 1) 
         {
             minmax.push_back(arr[0]);
             minmax.push_back(arr[0]);
             return minmax;
         }
  
         // no. of elements is even
         if(size%2 == 0)
         {
             minmax.push_back(min(arr[0],arr[1]));
             minmax.push_back(max(arr[0],arr[1]));
             begin_index = 2;
         }
         else
         {
             minmax.push_back(arr[0]);
             begin_index = 1;
         }
  
         // looping through the array considering 2 elements at once
         for(int i=begin_index;i<size;i+=2)
         {
             // comparing max element with maximum b/w ith and (i+1)th element
             if(max(arr[i],arr[i+1]) > minmax[max_index])
                 minmax[max_index] = max(arr[i],arr[i+1]);
             
             // comparing min element with minimum b/w ith and (i+1)th element
             if(min(arr[i],arr[i+1]) < minmax[min_index])
                 minmax[min_index] = min(arr[i],arr[i+1]);            
         }
  
         return minmax;
     }
 };
  
  
 int main()
 {
     //creating the ReverseAray object
     MinMax mnmx;
     vector<int> arr = {1,11,2,4,19,22,34,56,71,23,2,0,53};
     int arr_size = arr.size();
     vector<int> mnmax;
     mnmax = mnmx.minMaxPairCompare(arr, arr_size);
     if(mnmax.size() > 0)
     {
         cout<<"min "<<mnmax[0]<<" max "<<mnmax[1]<<endl;
     }
     
     return 0;
 } 

Also Read

Introduction to C++ STL
Basic Operations on Matrices in C++
Basic Operations on Matrices in C++
Five Ways to Calculate Power in C++
How to reverse an Array in C++?

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