Count of elements that can be deleted without disturbing the mean of the initial array
Given an array arr[] of N integers, the task is to find the count of elements from the array such that after removing them individually (only a single element can be deleted) from the array will not disturb the initial mean of the array.
Examples:
Input: arr[] = {1, 2, 3, 4, 5}
Output: 1
3 is the only element removing which
will not affect the mean of the array.
i.e. (1 + 2 + 4 + 5) / 4 = 12 / 4 = 3
which is the mean of the original array.
Input: arr[] = {5, 4, 3, 6}
Output: 0
Approach:
- Find the initial mean and the sum of the array elements and store them in the variables mean and sum respectively.
- Now, initialise count = 0 and for every element arr[i] if (sum – arr[i]) / (N – 1) = mean then increment the count.
- Print the count in the end.
Below is the implementation of the above approach:
C++
#include <bits/stdc++.h>
using namespace std;
int countElements( int arr[], int n)
{
int sum = 0;
for ( int i = 0; i < n; i++)
sum += arr[i];
float mean = ( float )sum / n;
int cnt = 0;
for ( int i = 0; i < n; i++) {
float newMean = ( float )(sum - arr[i]) / (n - 1);
if (newMean == mean)
cnt++;
}
return cnt;
}
int main()
{
int arr[] = { 1, 2, 3, 4, 5 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << countElements(arr, n);
return 0;
}
|
Java
class GFG
{
static int countElements( int arr[], int n)
{
int sum = 0 ;
for ( int i = 0 ; i < n; i++)
sum += arr[i];
float mean = ( float )sum / n;
int cnt = 0 ;
for ( int i = 0 ; i < n; i++)
{
float newMean = ( float )(sum - arr[i]) /
(n - 1 );
if (newMean == mean)
cnt++;
}
return cnt;
}
public static void main(String[] args)
{
int arr[] = { 1 , 2 , 3 , 4 , 5 };
int n = arr.length;
System.out.println(countElements(arr, n));
}
}
|
Python3
def countElements(arr, n):
Sum = 0
for i in range (n):
Sum + = arr[i]
mean = Sum / n
cnt = 0
for i in range (n):
newMean = ( Sum - arr[i]) / (n - 1 )
if (newMean = = mean):
cnt + = 1
return cnt
arr = [ 1 , 2 , 3 , 4 , 5 ]
n = len (arr)
print (countElements(arr, n))
|
C#
using System;
class GFG
{
static int countElements( int []arr, int n)
{
int sum = 0;
for ( int i = 0; i < n; i++)
sum += arr[i];
float mean = ( float )sum / n;
int cnt = 0;
for ( int i = 0; i < n; i++)
{
float newMean = ( float )(sum - arr[i]) /
(n - 1);
if (newMean == mean)
cnt++;
}
return cnt;
}
public static void Main(String[] args)
{
int []arr = { 1, 2, 3, 4, 5 };
int n = arr.Length;
Console.WriteLine(countElements(arr, n));
}
}
|
Javascript
<script>
function countElements(arr, n)
{
let sum = 0;
for (let i = 0; i < n; i++)
sum += arr[i];
let mean = sum / n;
let cnt = 0;
for (let i = 0; i < n; i++) {
let newMean = (sum - arr[i]) / (n - 1);
if (newMean == mean)
cnt++;
}
return cnt;
}
let arr = [ 1, 2, 3, 4, 5 ];
let n = arr.length;
document.write(countElements(arr, n));
</script>
|
Time Complexity: O(N)
Auxiliary Space: O(1)
Last Updated :
04 Jun, 2022
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