include<bits/stdc++.h>

using namespace std;
long long n,dem,m,a[1000000],s[1000000];
int main()
{
cin>>n;
cin>>m;
dem=0;
memset(s,0,sizeof(s));
for(int i=1;i<=n;i++)
{cin>>a[i];
s[a[i]]++;}
for(int i=1;i<=m;i++)
if(s[i]!=0){
for(int j=i+1;j<=m;j++)
if(i+j<=m)
{if(s[i]>s[j])dem=dem+s[j];
else dem=dem+s[i];}
else break;}
for(int i=1;i<=m;i++)
{
if(s[i]=1) dem=dem+1;
if(s[i]>1) dem=dem+(s[i]*(s[i]-1))/2;
}
cout<<dem;

}

bin lê
i'm tula

)
tin học là cái gì vậy :)
lamo
chip chap du bi :)
https://lqdoj.edu.vn/media/profile_images/user_201731.png nhấn vào

nadja

DPNTG

.