C++ program to find minimum scalar of two vectors

Finding the minimum scalar product in C++

Here, in this page we will discuss the program to find the minimum scalar product in C++ programming language. We are given with two arrays and need to print the value of minimum scalar product that obtained.

Find minimum scalar product in Cpp

Method Discussed :

  • Method 1 : Without using inbuilt sort() function for sorting.
  • Method 2 : Using sort() function for sorting.

Let’s discuss both methods one by one in brief,

Method 1 :

  • Sort the first array in ascending order,
  • Sort the second array in descending order.
  • Declare a variable say product = 0.
  • Run a loop from index 0 to n
  • Set product += (arrr1[i]*arr2[i])
  • After complete iteration print product.

Time and Space Complexity :

  • Time Complexity : O(n2)
  • Space Complexity : O(1)
Minimum scalar product in C++

Method 1 : Code in C++

Run
#include<bits/stdc++.h>
using namespace std;

int main(){

   int arr1[] = {1, 2, 6, 3, 7};
   int arr2[] = {10, 7, 45, 3, 7};

   int n = sizeof(arr1)/sizeof(arr1[0]);


   //Sort arr1 in ascending order
   for(int i=0; i<n; i++){
       for(int j=i+1; j<n; j++){ if(arr1[i]>arr1[j]){
               int temp = arr1[i];
               arr1[i] = arr1[j];
               arr1[j] = temp;
           }
       }
   }

   //Sort arr2 in descending order
   for(int i=0; i<n; i++){
       for(int j=i+1; j<n; j++){
           if(arr2[i]<arr2[j]){
                int temp = arr2[i];
                arr2[i] = arr2[j];
                arr2[j] = temp;
           }
       }
    }

    int product = 0;
    for(int i=0; i<n; i++)
        product += arr1[i]*arr2[i];

    cout<< product;

}

Output

149

Method 2 :

In this method we will use inbuilt sort function to sort the array.

  • For, sorting arr1 in ascending order, use sort(arr1, arr1+n)
  • For, sorting arr2 in descending order, use sort(arr2, arr2+n, greater()).

Time and Space Complexity :

  • Time Complexity : O(n log(n))
  • Space Complexity : O(1)

Method 2 : Code in C++

Run

#include<bits/stdc++.h>
using namespace std;

int main(){

   int arr1[] = {1, 2, 6, 3, 7};
   int arr2[] = {10, 7, 45, 3, 7};

   int n = sizeof(arr1)/sizeof(arr1[0]);


   //Sort arr1 in ascending order
   sort(arr1, arr1+n);
//Sort arr2 in descending order
sort(arr2, arr2+n, greater<int>()); int product = 0; 
for(int i=0; i<n; i++) product += arr1[i]*arr2[i]; 
cout<< product; 
}

Output

149