很显然，先把所有学生排序并且分组
然后，把两个组合并
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#define int long long
using namespace std;
int n,m,k,x;
int a[2000001];
int fa[2000001];
int cnt;
int co[3000001];
int find(int x){
return fa[x]==x?fa[x]:fa[x]=find(fa[x]);
}
signed main(){
scanf("%lld%lld%lld",&n,&k,&x);
for(int i=1;i<=n;++i){
scanf("%lld",&a[i]);
}
sort(a+1,a+n+1);
for(int i=2;i<=n;++i){
if(a[i]-a[i-1]<=x){
fa[i]=i-1;
}else{
fa[i]=i;
}
}
fa[1]=1;
for(int i=2;i<=n;++i){
if(find(fa[i])!=find(fa[i-1])){
cnt++;
co[cnt]=(a[i]-a[i-1]-x)/x+(((a[i]-a[i-1])%x)!=0);
}
}
cnt++;
int tem=cnt;
sort(co+1,co+cnt);
for(int i=1;i<cnt;++i){
// cout<<co[i]<<endl;
if(k>=co[i]){
tem--;
k-=co[i];
}else
break;
}
cout<<tem;
return 0;
}