Find elements larger than half of the elements in an array

Given an array of n elements, the task is to find the elements that are greater than half of elements in an array. In case of odd elements, we need to print elements larger than floor(n/2) elements where n is total number of elements in array.

Examples :

Input :  arr[] = {1, 6, 3, 4}
Output : 4 6
Input  :  arr[] = {10, 4, 2, 8, 9}
Output :  10 9 8

A naive approach is to take an element and compare it with all other elements and if it is greater, then increment the count and then check if count is greater than n/2 elements, then print.

Algorithm:

1. Declare a function named greaterThanHalf that takes an integer array arr and an integer n as inputs.
2. Traverse through each element of the array from index i = 0 to i = n-1.
3. Declare a variable count and initialize it to 0.
4. Traverse through each element of the array from index j = 0 to j = n-1.
5. If the element at index j is less than the element at index i, increment count by 1.
6. If count is greater than or equal to n/2, print the element at index i.

Below is the implementation of the approach:

C++

// C++ code for the approach

#include <bits/stdc++.h>

using namespace std;

// Function to find the elements that are greater
// than half of elements in an array
void greaterThanHalf(int arr[], int n) {
      // traversing each element of array
    for (int i = 0; i < n; i++) {
        int count = 0;
          // again traversing each element to
          // count from how many numbers in the
          // array arr[i] is greater
        for (int j = 0; j < n; j++) {
            if (arr[j] < arr[i])
                count++;
        }

          // if count is greater than n/2
          // this is the element so print it
        if (count >= n / 2)
            cout << arr[i] << " ";
    }
}

// Driver's code
int main() {
      // Input array
    int arr[] = { 1, 3, 6, 1, 0, 9 };
    int n = sizeof(arr) / sizeof(arr[0]);

      // Function Call
    greaterThanHalf(arr, n);

    return 0;
}

Java

public class Main {

    // Function to find the elements that are greater
    // than half of elements in an array
    static void greaterThanHalf(int arr[], int n) {
        // traversing each element of array
        for (int i = 0; i < n; i++) {
            int count = 0;
            // again traversing each element to
            // count from how many numbers in the
            // array arr[i] is greater
            for (int j = 0; j < n; j++) {
                if (arr[j] < arr[i])
                    count++;
            }

            // if count is greater than n/2
            // this is the element so print it
            if (count >= n / 2)
                System.out.print(arr[i] + " ");
        }
    }

    // Driver's code
    public static void main(String[] args) {
        // Input array
        int arr[] = { 1, 3, 6, 1, 0, 9 };
        int n = arr.length;

        // Function Call
        greaterThanHalf(arr, n);
    }
}

Python3

# Function to find the elements that are greater
# than half of elements in an array


def greaterThanHalf(arr, n):
    # traversing each element of array
    for i in range(n):
        count = 0
        # again traversing each element to
        # count from how many numbers in the
        # array arr[i] is greater
        for j in range(n):
            if (arr[j] < arr[i]):
                count += 1
        # if count is greater than n/2
        # this is the element so print it
        if (count >= n / 2):
            print(arr[i], end=" ")


# Driver's code
arr = [1, 3, 6, 1, 0, 9]
n = len(arr)
greaterThanHalf(arr, n)

C#

using System;

class Program
{
    // Function to find the elements that are greater
    // than half of elements in an array
    static void GreaterThanHalf(int[] arr, int n)
    {
        // Traversing each element of the array
        for (int i = 0; i < n; i++)
        {
            int count = 0;

            // Again traversing each element to
            // count how many numbers in the array
            // arr[i] is greater
            for (int j = 0; j < n; j++)
            {
                if (arr[j] < arr[i])
                    count++;
            }

            // If count is greater than or equal to n/2
            // this is the element, so print it
            if (count >= n / 2)
                Console.Write(arr[i] + " ");
        }
    }

    // Driver's code
    static void Main(string[] args)
    {
        // Input array
        int[] arr = { 1, 3, 6, 1, 0, 9 };
        int n = arr.Length;

        // Function Call
        GreaterThanHalf(arr, n);
    }
}
// This code is contributed by shivamgupta0987654321

Javascript

// Javascript code for the approach

// Function to find the elements that are greater
// than half of elements in an array
function greaterThanHalf(arr, n) {
    // traversing each element of array
    for (let i = 0; i < n; i++) {
        let count = 0;
        // again traversing each element to
        // count from how many numbers in the
        // array arr[i] is greater
        for (let j = 0; j < n; j++) {
            if (arr[j] < arr[i])
                count++;
        }

        // if count is greater than n/2
        // this is the element so print it
        if (count >= Math.floor(n / 2))
            console.log(arr[i] + " ");
    }
}
// Driver's code

// Input array
let arr = [1, 3, 6, 1, 0, 9];
let n = arr.length;

// Function Call
greaterThanHalf(arr, n);

Output

3 6 9 

Time Complexity: O(N*N) as two nested loops are executing both from 1 to N where N is size of the input array.

Space Complexity: O(1) as no extra space has been used.

An efficient method is to sort the array in ascending order and then print last ceil(n/2) elements from sorted array. 
Below is the implementation of this sorting based approach.

Implementation:

C++

// C++ program to find elements that are larger than
// half of the elements in array
#include <bits/stdc++.h>
using namespace std;

// Prints elements larger than n/2 element
void findLarger(int arr[], int n)
{
    // Sort the array in ascending order
    sort(arr, arr + n);

    // Print last ceil(n/2) elements
    for (int i = n-1; i >= n/2; i--)
        cout << arr[i] << " ";
}

// Driver program
int main()
{
    int arr[] = {1, 3, 6, 1, 0, 9};
    int n = sizeof(arr)/sizeof(arr[0]);
    findLarger(arr, n);
    return 0;
}

Java

// Java program to find elements that are
// larger than half of the elements in array
import java.util.*;

class Gfg
{
    // Prints elements larger than n/2 element
    static void findLarger(int arr[], int n)
    {
        // Sort the array in ascending order
        Arrays.sort(arr);

        // Print last ceil(n/2) elements
        for (int i = n-1; i >= n/2; i--)
            System.out.print(arr[i] + " ");
    }

    // Driver program
    public static void main(String[] args)
    {
        int arr[] = {1, 3, 6, 1, 0, 9};
        int n = arr.length;
        findLarger(arr, n);
    }
}

// This code is contributed by Raghav Sharma

Python3

# Python program to find elements that are larger than
# half of the elements in array
# Prints elements larger than n/2 element
def findLarger(arr,n):

    # Sort the array in ascending order
    x = sorted(arr)

    # Print last ceil(n/2) elements
    for i in range(n//2,n):
        print(x[i],end=" ")

# Driver program
arr = [1, 3, 6, 1, 0, 9]
n = len(arr);
findLarger(arr,n)

# This code is contributed by Afzal Ansari

C#

// C# program to find elements
// that are larger than half
// of the elements in array
using System;

class GFG
{
    // Prints elements larger
    // than n/2 element
    static void findLarger(int []arr,
                           int n)
    {
        // Sort the array
        // in ascending order
        Array.Sort(arr);

        // Print last ceil(n/2) elements
        for (int i = n - 1; i >= n / 2; i--)
            Console.Write(arr[i] + " ");
    }

    // Driver Code
    public static void Main()
    {
        int []arr = {1, 3, 6, 1, 0, 9};
        int n = arr.Length;
        findLarger(arr, n);
    }
}

// This code is contributed
// by nitin mittal.

Javascript

<script>

// JavaScript program to find elements that are
// larger than half of the elements in array

// Prints elements larger than n/2 element
function findLarger(arr, n)
{

    // Sort the array in ascending order
    arr.sort();

    // Print last ceil(n/2) elements
    for(let i = n - 1; i >= n / 2; i--)
        document.write(arr[i] + " ");
}

// Driver Code
let arr = [1, 3, 6, 1, 0, 9];
let n = arr.length;
findLarger(arr, n);

// This code is contributed by chinmoy1997pal

</script>

PHP

<?php
// PHP program to find elements
// that are larger than half of
// the elements in array

// Prints elements larger
// than n/2 element
function findLarger($arr, $n)
{
    // Sort the array in
    // ascending order
    sort($arr);

    // Print last ceil(n/2) elements
    for ($i = $n - 1; $i >= $n / 2; $i--)
        echo $arr[$i] , " ";
}

// Driver Code
$arr = array(1, 3, 6, 1, 0, 9);
$n = count($arr);
findLarger($arr, $n);

// This code is contributed by anuj_67.
?>

Output

9 6 3 

Time Complexity: O(n*log(n))
Auxiliary Space: O(1)

This article is contributed by Sahil Chhabra . If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.