ac

#include<bits/stdc++.h>//1
using namespace std;
long long n,c,a[200005],sum;
int main(){
	cin>>n>>c;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++){ 
		int x=upper_bound(a+1,a+n+1,a[i]+c)-a;
		int y=lower_bound(a+1,a+n+1,a[i]+c)-a;
		x=x-y;
		sum+=x;
	}
	cout<<sum;
	return 0;
}

92

#include<bits/stdc++.h>//1
using namespace std;
long long n,c,a[200005],sum;
int main(){
	scanf("%d%d",&n,&c);
	for(int i=1;i<=n;i++){
		scanf("%d",&a[i]);
	}
	sort(a+1,a+n+1);
	for(int i=1;i<=n;i++){ 
		int x=upper_bound(a+1,a+n+1,a[i]+c)-a;
		int y=lower_bound(a+1,a+n+1,a[i]+c)-a;
		sum+=x-y;
	}
	printf("%d",sum);
	return 0;
}

为什么会这样呢？求助大佬，谢谢！