Count of elements which are not at the correct position

Given an array arr[] of N elements and the task is to count the number of elements from this array which are not at the correct position. An element is said to be in an incorrect position if its position changes in the array when the array is sorted.

Examples:

Input: arr[] = {1, 2, 6, 2, 4, 5}
Output: 4
Array in the sorted form will be {1, 2, 2, 4, 5, 6}



Input: arr[] = {1, 2, 3, 4}
Output: 0
All the elements are already sorted.

Approach: First copy the array elements in another array say B[] then sort the given array. Start traversing the array and for every element if arr[i] != B[i] then it is the element which was not at the right position in the given array.

Below is the implementation of the above approach:

C++

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// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
  
// Function to return the count of
// elements which are not in
// the correct position when sorted
int cntElements(int arr[], int n)
{
  
    // To store a copy of the
    // original array
    int copy_arr[n];
  
    // Copy the elements of the given
    // array to the new array
    for (int i = 0; i < n; i++)
        copy_arr[i] = arr[i];
  
    // To store the required count
    int count = 0;
  
    // Sort the original array
    sort(arr, arr + n);
    for (int i = 0; i < n; i++) {
  
        // If current element was not
        // at the right position
        if (arr[i] != copy_arr[i]) {
            count++;
        }
    }
    return count;
}
  
// Driver code
int main()
{
    int arr[] = { 1, 2, 6, 2, 4, 5 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    cout << cntElements(arr, n);
  
    return 0;
}

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Java

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// Java implementation of the approach 
import java.util.*;
  
class GFG 
{
      
    // Function to return the count of 
    // elements which are not in 
    // the correct position when sorted 
    static int cntElements(int arr[], int n) 
    
      
        // To store a copy of the 
        // original array 
        int copy_arr[] = new int[n]; 
      
        // Copy the elements of the given 
        // array to the new array 
        for (int i = 0; i < n; i++) 
            copy_arr[i] = arr[i]; 
      
        // To store the required count 
        int count = 0
      
        // Sort the original array 
        Arrays.sort(arr); 
          
        for (int i = 0; i < n; i++) 
        
      
            // If current element was not 
            // at the right position 
            if (arr[i] != copy_arr[i])
            
                count++; 
            
        
        return count; 
    
      
    // Driver code 
    public static void main (String[] args)
    
        int arr[] = { 1, 2, 6, 2, 4, 5 }; 
        int n = arr.length; 
      
        System.out.println(cntElements(arr, n)); 
    
}
  
// This code is contributed by AnkitRai01

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Python3

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# Python3 implementation of the approach 
  
# Function to return the count of 
# elements which are not in 
# the correct position when sorted 
def cntElements(arr, n) :
  
    # To store a copy of the 
    # original array 
    copy_arr = [0] *
  
    # Copy the elements of the given 
    # array to the new array 
    for i in range(n): 
        copy_arr[i] = arr[i] 
  
    # To store the required count 
    count = 0
  
    # Sort the original array 
    arr.sort() 
    for i in range(n): 
  
        # If current element was not 
        # at the right position 
        if (arr[i] != copy_arr[i]) : 
            count += 1
              
    return count
      
# Driver code 
arr = [ 1, 2, 6, 2, 4, 5
n = len(arr) 
  
print(cntElements(arr, n)) 
  
# This code is contributed by
# divyamohan123

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C#

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// C# implementation of the approach 
using System;
  
class GFG 
{
      
    // Function to return the count of 
    // elements which are not in 
    // the correct position when sorted 
    static int cntElements(int [] arr, int n) 
    
      
        // To store a copy of the 
        // original array 
        int [] copy_arr = new int[n]; 
      
        // Copy the elements of the given 
        // array to the new array 
        for (int i = 0; i < n; i++) 
            copy_arr[i] = arr[i]; 
      
        // To store the required count 
        int count = 0; 
      
        // Sort the original array 
        Array.Sort(arr); 
          
        for (int i = 0; i < n; i++) 
        
      
            // If current element was not 
            // at the right position 
            if (arr[i] != copy_arr[i])
            
                count++; 
            
        
        return count; 
    
      
    // Driver code 
    public static void Main (String[] args)
    
        int [] arr = { 1, 2, 6, 2, 4, 5 }; 
        int n = arr.Length; 
      
        Console.WriteLine(cntElements(arr, n)); 
    
}
  
// This code is contributed by Mohit kumar

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Output:

4

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