rt 题 70pts 代码

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
int a[1000001];
int main(){
//	freopen("pair.in","r",stdin);
//	freopen("pair.out","w",stdout);
	int n,k;
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	int ans=0;
	if(a[1]==a[n]){
		cout<<0;
		return 0;
	}
	int t=2;
	for(int i=1;i<=n;i++){
		while((t<=i||abs(a[t]-a[i])<=k)&&t<=n){
			t++;
		}
		t--;
		ans+=(t-i);
	} 
	cout<<ans;
   	return 0;
} 
//6
//1 2 3 4 5 6
//  i