Apartments.cpp

#include<bits/stdc++.h>
using namespace std;
#define INF 2147483647
#define INFL 9223372036854775807
#define pii pair<int,int>
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define ll long long
#define ull unsigned long long
#define M 1000000007
#define FASTIO ios_base::sync_with_stdio(false);cin.tie(NULL); cout.tie(NULL);
#define take(x) scanf("%d",&x)
#define DE(x) printf("\ndebug %d\n",x);
#define vout(x) for(int i=0;i<x.size();i++) printf("%d ",x[i]);
#define pie acos(-1)
#define MOD 998244353

int main(){
    int n,m,k;
    cin>>n>>m>>k;
    int aparts[n],res[m];
    for(int i=0;i<n;i++){
        cin>>aparts[i];
    }
    for(int i=0;i<m;i++){
        cin>>res[i];
    }
    sort(aparts,aparts+n);
    sort(res,res+m);
    int i = 0,j = 0,ans = 0;
    while(i<n and j<m){
        if( abs( aparts[i]-res[j])<=k ){
            ans++;
            i++;
            j++;
        } else if( aparts[i]-res[j]>k ){
            j++;
        } else{
            i++;
        }

    }
    cout<<ans;
}