#include <bits/stdc++.h>
using namespace std;
 
int countPairsLessEqualK(vector<int> &arr, int k){
	int count = 0, n = arr.size();
 
	sort(arr.begin(), arr.end());
 
	for (int i = 0, j = 0; j < n; j++){
		int d = arr[j] - arr[i];
 
		while (d > k){
			i++;
			d = arr[j] - arr[i];
		}
 
		count += (j - i + 1);
	}
 
	return (count - n);
}
 
int main() {
	// your code goes here
 
	vector<int> arr = {1, 5, 3, 4, 2};
	cout << countPairsLessEqualK(arr, 2);
	return 0;
}

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