# Count elements such that there are exactly X elements with values greater than or equal to X

Given an array *arr* of *N* integers, the task is to find the number of elements that satisfy the following condition:

If the element is *X* then there has to be exactly *X* number of elements in the array (excluding the number *X*) which are greater than or equal to *X*

**Examples:**

Input:arr[] = {1, 2, 3, 4}Output:1 Only element 2 satisfies the condition as there are exactly 2 elements which are greater than or equal to 2 (3, 4) except 2 itself.Input:arr[] = {5, 5, 5, 5, 5}Output:0

**Approach:** The problem involves efficient searching for each arr[i] element the number of arr[j]’s (i != j) which are greater than or equal to arr[i].

- Sort the array in ascending order.
- For every element arr[i], using binary search get the count of all the elements that are greater than or equal to arr[i] except arr[i] itself.
- If the count is equal to arr[i] then increment the result.
- Print the value of the result in the end.

Below is the implementation of the above approach:

`// C++ implementation of the approach ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` `#define ll long long ` ` ` `ll ` `int` `getCount(vector<ll ` `int` `> v, ` `int` `n) ` `{ ` ` ` `// Sorting the vector ` ` ` `sort((v).begin(), (v).end()); ` ` ` `ll ` `int` `cnt = 0; ` ` ` `for` `(ll ` `int` `i = 0; i < n; i++) { ` ` ` ` ` `// Count of numbers which ` ` ` `// are greater than v[i] ` ` ` `ll ` `int` `tmp = v.end() - 1 ` ` ` `- upper_bound((v).begin(), (v).end(), v[i] - 1); ` ` ` ` ` `if` `(tmp == v[i]) ` ` ` `cnt++; ` ` ` `} ` ` ` `return` `cnt; ` `} ` ` ` `// Driver code ` `int` `main() ` `{ ` ` ` `ll ` `int` `n; ` ` ` `n = 4; ` ` ` `vector<ll ` `int` `> v; ` ` ` `v.push_back(1); ` ` ` `v.push_back(2); ` ` ` `v.push_back(3); ` ` ` `v.push_back(4); ` ` ` ` ` `cout << getCount(v, n); ` ` ` `return` `0; ` `} ` |

*chevron_right*

*filter_none*

**Output:**

1

## Recommended Posts:

- Noble integers in an array (count of greater elements is equal to value)
- Count of elements whose absolute difference with the sum of all the other elements is greater than k
- Replace repeating elements with greater that greatest values
- Sum of elements in an array with frequencies greater than or equal to that element
- Adding elements of an array until every element becomes greater than or equal to k
- Count subarrays with all elements greater than K
- Count sub-arrays which have elements less than or equal to X
- Count pairs in an array such that both elements has equal set bits
- Count of smaller or equal elements in sorted array
- Count of index pairs with equal elements in an array
- Count subarrays with equal number of occurrences of two given elements
- Count elements smaller than or equal to x in a sorted matrix
- Count elements less than or equal to a given value in a sorted rotated array
- Find all elements in array which have at-least two greater elements
- Replace two consecutive equal values with one greater

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.