有一个TLE不知道怎么优化了

#include<iostream>
#include<algorithm>
#include<string.h>
using namespace std;


int main ()
{    
	int n, c, a[200010];
	cin >> n >> c;
	
	for(int i = 0; i < n; i ++) cin >> a[i];
	
	sort(a,a + n);
	int cnt = 0;
	for(int i = n - 1; i >= 1; i --)
	{
		int l = 0,r = i,x = a[i] - c;
		while(l < r)
		{
			int mid = (l + r)/2;
			if(a[mid] >= x) r = mid;
			else l = mid + 1;
		}
		for(int i = l; a[i] == x; i ++)
		{
			cnt ++;
		}
	}
	cout << cnt;
	return 0; 
}