#include<bits/stdc++.h>
#define N 200005
#define int long long
#define db double
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int T,n,m,k,a[N],op,x,y,z,ans,last;
priority_queue<int>q;
void swap(int &x,int &y){int t=x;x=y;y=t;}
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
void ckmax(int &x,int y){if(y>x)x=y;}
void ckmin(int &x,int y){if(y<x)x=y;}
int fp(int a,int n,int mod){
    int ans=1;
    while(n){
        if(n&1)ans=ans*a%mod;
        a=a*a%mod;
        n>>=1;
    }
    return ans;
}
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int po(int x){return x*x;}
int sub(int x,int y){return x>y?x-y:y-x;}
int ab(int x){return x<0?-x:x;}
int read(){
    int sum=0;bool f=0;char c=getchar();
    for(;c<48||c>57;c=getchar())if(c==45)f=1;
    for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
    return f?-sum:sum;
}
int gs(int l,int k,int x,int y){
    if(!k)return 0;
    int ans=max(x,l-y);k--;
    l-=y-x;
    return ans+l*k;
}
signed main(){
    freopen("fly.in","r",stdin);freopen("fly.out","w",stdout);
    T=read();
    while(T--){
        n=read();k=read();m=read();
        fo(i,1,n)a[i]=read();
        sort(a+1,a+n+1);
        fo(i,1,n-1)q.push(a[i+1]-a[i]>>1);
        ans=gs(m,k,a[1],a[n]);
        int sum=0;
        while(!q.empty()&&k){
            int x=q.top();q.pop();
            k--;
            a[1]+=x;a[n]-=x;
            sum+=x;
            ckmax(ans,sum+gs(m,k,a[1],a[n]));
        }
        printf("%lld\n",ans);
        while(!q.empty())q.pop();
    }
    return 0;
}