Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Count integers in an Array which are multiples their bits counts

  • Last Updated : 12 May, 2021

Given an array arr[] of N elements, the task is to count all the elements which are a multiple of their set bits count.
Examples: 
 

Input : arr[] = { 1, 2, 3, 4, 5, 6 }
Output : 4
Explanation :
There numbers which are multiple of their setbits count are { 1, 2, 4, 6 }.

Input : arr[] = {10, 20, 30, 40}
Output : 3
Explanation :
There numbers which are multiple of their setbits count are { 10, 20, 40 }

 

Approach: Loop through each array elements one by one. Count the set bits of every number in the array. Check if the current integer is a multiple of its set bits count or not. If ‘yes’ then increment the counter by 1, else skip that integer. 
Below is the implementation of above approach: 
 

C++




#include <bits/stdc++.h>
using namespace std;
 
// Function to find the count of numbers
// which are multiple of its set bits count
int find_count(vector<int>& arr)
{
    // variable to store count
    int ans = 0;
 
    // iterate over elements of array
    for (int i : arr) {
 
        // Get the set-bits count of each element
        int x = __builtin_popcount(i);
 
        // Check if the setbits count
        // divides the integer i
        if (i % x == 0)
 
            // Increment the count
            // of required numbers by 1
            ans += 1;
    }
 
    return ans;
}
 
// Driver code
int main()
{
    vector<int> arr
        = { 1, 2, 3, 4, 5, 6 };
 
    cout << find_count(arr);
 
    return 0;
}

Java




class GFG{
  
// Function to find the count of numbers
// which are multiple of its set bits count
static int find_count(int []arr)
{
    // variable to store count
    int ans = 0;
  
    // iterate over elements of array
    for (int i : arr) {
  
        // Get the set-bits count of each element
        int x = Integer.bitCount(i);
  
        // Check if the setbits count
        // divides the integer i
        if (i % x == 0)
  
            // Increment the count
            // of required numbers by 1
            ans += 1;
    }
  
    return ans;
}
  
// Driver code
public static void main(String[] args)
{
    int []arr
        = { 1, 2, 3, 4, 5, 6 };
  
    System.out.print(find_count(arr));
  
}
}
 
// This code contributed by Princi Singh

Python3




# Python3 implementation of above approach
 
# function to return set bits count
def bitsoncount(x):
    return bin(x).count('1')
 
# Function to find the count of numbers
# which are multiple of its set bits count
def find_count(arr) :
    # variable to store count
    ans = 0
 
    # iterate over elements of array
    for i in arr :
 
        # Get the set-bits count of each element
        x = bitsoncount(i)
 
        # Check if the setbits count
        # divides the integer i
        if (i % x == 0):
 
            # Increment the count
            # of required numbers by 1
            ans += 1
 
    return ans
 
# Driver code
arr = [ 1, 2, 3, 4, 5, 6 ]
 
print(find_count(arr))
 
# This code is contributed by Sanjit_Prasad

C#




using System;
 
public class GFG{
   
// Function to find the count of numbers
// which are multiple of its set bits count
static int find_count(int []arr)
{
    // Variable to store count
    int ans = 0;
   
    // Iterate over elements of array
    foreach (int i in arr) {
   
        // Get the set-bits count of each element
        int x = bitCount(i);
   
        // Check if the setbits count
        // divides the integer i
        if (i % x == 0)
   
            // Increment the count
            // of required numbers by 1
            ans += 1;
    }
   
    return ans;
}
static int bitCount(long x)
{
    int setBits = 0;
    while (x != 0) {
        x = x & (x - 1);
        setBits++;
    }
    return setBits;
}
   
// Driver code
public static void Main(String[] args)
{
    int []arr
        = { 1, 2, 3, 4, 5, 6 };
   
    Console.Write(find_count(arr));
   
}
}
// This code contributed by Princi Singh

Javascript




<script>
  
// Function to find the count of numbers
// which are multiple of its set bits count
function find_count(arr)
{
    // Variable to store count
    var ans = 0;
   
    // Iterate over elements of array
    for (var i=0;i<=arr.length;i++) {
   
        // Get the set-bits count of each element
        var x = bitCount(i);
   
        // Check if the setbits count
        // divides the integer i
        if (i % x == 0)
   
            // Increment the count
            // of required numbers by 1
            ans += 1;
    }
   
    return ans;
}
function bitCount( x)
{
    var setBits = 0;
    while (x != 0) {
        x = x & (x - 1);
        setBits++;
    }
    return setBits;
}
var arr = [ 1, 2, 3, 4, 5, 6 ];
  document.write(find_count(arr));
   
  // This code contributed by SoumikMondal
</script>

Output : 
 

4

Time complexity:- O(nlog(max(arr[])), where n is the size of the array, 
Space complexity:- O(1)
 


My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!