0分求条，找出思路的错误即可（回复就关）

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn=2e5+10;
int n,c,ans;
int a[maxn];
int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if (ch=='-'){f=-1;}ch=getchar();}
	while(ch<='9'&&ch>='0'){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}
	return f*x;
}
map<int,int> mp;
signed main()
{
	n=read(),c=read();
	for (int i=1;i<=n;++i)
	{
		a[i]=read();
	}	
	for (int i=1;i<=n;++i)
	{
		ans+=mp[a[i]];
		mp[a[i]+c]++;
	}
	printf("%d",ans);	
}