rt 题目

#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,m;
   cin>>n>>m;
   for(int i=1;i<=n;i++){
      cin>>a[i];
   }
   sort(a+1,a+n+1);
   int ans=0;
   for(int i=1;i<=n;i++){
      if(abs(a[i+1]-a[i])<=m){
         for(int j=n;j>=i+1;j--){
            if(abs(a[j]-a[i]<=m)){
               ans+=j-i;
               break;
            }
         }
      }
      
   }
   cout<<ans;
   return 0;
}