Count occurrences of the average of array elements with a given number

Given an array of N integers and an integer x. For every integer of the array a[i], the task is to calculate the count of numbers in the array with value equals to the average of element a[i] and x. That is, the number of occurrences of the (average of element a[i] and x) in the array.

Examples:

Input: arr[] = {2, 0, 4, 6, 2}, x = 2
Output: 2 0 0 1 2
For x = 2, the average values for 2, 0, 4, 6, 2 would be 2, 1, 3, 4, 2 respectively. So, the count array would result in 2, 0, 0, 1, 2.

Input: arr[] = {9, 5, 2, 4, 0, 3}, x = 3
Output: 0 1 1 1 0 1
For x = 3, the average values for 9, 5, 2, 4, 0, 3 would be 6, 4, 2, 3, 1, 2 respectively. So, the count array would result in 0, 1, 1, 1, 0, 1.

Approach:

  1. Traverse the array and map every element with its count of occurrence in the array.
  2. Now traverse the array again, take the average of the array element and given x and check for its value in the map.

Below is the implementation of the above approach:

Java

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// Java program to find the count of
// occurrences of the average of array
// elements with a given number
import java.io.*;
import java.util.*;
import java.lang.*;
  
class GFG {
  
    // Function to to find the count of
    // occurrences of the average of array
    // elements with a given number
    static void getAverageCountArray(int[] a, int x, int N)
    {
        // Map to store count of occurrence
        // of every array element in the array
        HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
  
        // Array that stores the average
        // count for given array
        int[] avg = new int[N];
        int val, av;
  
        for (int i = 0; i < N; i++) {
            // first occurrence of a[i]
            if (!map.containsKey(a[i])) {
                map.put(a[i], 1);
            }
  
            // element has already occurred before
            // so increase its count
            else {
                // gives current count of a[i]
                val = map.get(a[i]);
                val++;
                map.remove(a[i]);
                map.put(a[i], val);
            }
        }
  
        for (int i = 0; i < N; i++) {
            av = (a[i] + x) / 2;
            if (map.containsKey(av)) {
                val = map.get(av);
                avg[i] = val;
            }
        }
  
        // Printing the average count array
        for (int i = 0; i < N; i++) {
            System.out.print(avg[i] + " ");
        }
    }
  
    // Driver code
    public static void main(String args[])
    {
        int[] a = { 2, 0, 4, 6, 2 };
        int x = 2;
  
        int N = a.length;
  
        getAverageCountArray(a, x, N);
    }
}

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Python3

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# Python3 program to find the count of 
# occurrences of the average of array 
# elements with a given number 
  
# Function to to find the count of 
# occurrences of the average of array 
# elements with a given number 
def getAverageCountArray(a, x, N): 
       
    # Dictionary to store count of occurrence 
    # of every array element in the array 
    map = {}
      
    # Array that stores the average 
    # count for given array 
    avg = [0] *
    
    for i in range(N):  
        # first occurrence of a[i] 
        if a[i] not in map:  
            map[a[i]] =  1 
               
        # element has already occurred before 
        # so increase its count 
        else
            # gives current count of a[i] 
            map[a[i]] += 1
              
    for i in range(N):  
        av = (a[i] + x) // 2 
          
        if av in map:
            val = map[av] 
            avg[i] = val 
               
    # Printing the average count array 
    for i in range(N):
        print(avg[i], end = " "
           
       
if __name__ == "__main__":
       
    a = [2, 0, 4, 6, 2]  
    x = 2 
    
    N = len(a) 
    getAverageCountArray(a, x, N) 
      
# This code is contributed by Rituraj Jain

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Output:

2 0 0 1 2


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Improved By : rituraj_jain



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