第二个测试点复制不进去,有200000个数据,然后5个WA2个RE
#include<bits/stdc++.h>
using namespace std;
const int N=200010;
int n,m;
int a[N],sum[N];
int l,r,mid,maxn,cnt;
int main(){
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++){
scanf("%d",&a[i]);
maxn=max(maxn,a[i]);
sum[a[i]]++;
}
for(int i=1;i<=n;i++){
l=1,r=maxn;
while(l<=r){
mid=(l+r)/2;
if(a[i]<mid)break;
if(a[i]-mid==m){
cnt+=sum[mid];
break;
}
if(a[i]-mid<m)r=mid-1;
if(a[i]-mid>m)l=mid+1;
}
}
printf("%d",cnt);
return 0;
}