đề bài :
https://lqdoj.edu.vn/problem/high
code tôi
#include <bits/stdc++.h>
using namespace std;
long long n,i,x,t,t2,a[10000005],j,d,b[10000005],m,chettui,ok;
map<long long,long long> s;
map<long long,long long> s2;
int main()
{
ios_base::sync_with_stdio(0);
cin>>n>>m>>x;
for(i=1;i<=n;i++)
{
cin>>a[i];
s2[a[i]]++;
}
for(i=1;i<=m;i++)
{
cin>>b[i];
s[b[i]]++;
}
sort(a+1,a+1+n);
sort(b+1,b+1+m);
for(i=1;i<=n;i++)
{
if(ok==1||a[i]!=a[i-1])
{
t=a[i]-x;
t2=a[i]+x;
for(j=t;j<=t2;j++)
{
if(s[j]>=1)
{
chettui=min(s[j],s2[a[i]]);
if(chettui==s[j])
{
ok=1;
}
else ok=0;
d=d+chettui;
s[j]=s[j]-chettui;
s2[a[i]]=s2[a[i]]-chettui;
break;
}
}
}
}
cout<<d;
}