#ifdef __AVX2__
#pragma GCC target "avx2"
#endif
#pragma GCC optimize "O3"
#pragma GCC optimize "unroll-loops"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define int long long
#define elif else if
#define all(l) begin(l),end(l)
#define rall(l) rbegin(l),rend(l)
#define append push_back
#define print(l) for(auto i:l) cout<<i<<' '; cout<<endl;
#define pprint(a,b) cout<<a<<' '<<b<<endl;
#define inp(l) for(auto &i:l) cin>>i;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pai make_pair
#define endl "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define vec vector
// const int mod=998244353;
const int mod1=998244353;
const int mod=1e9+7;
const int N=2e5+5;
int iter=1,itera=1;
void solve(){
int n,p,q;
cin>>n>>p>>q;
p=min(p,n);
vec<int>a(n);
inp(a);
a.insert(begin(a),-1e18);
sort(all(a));
map<int,int>d;
for(auto i:a) d[i]=1e18;
for(int i=0;i<=n;i++)
d[a[i]]=min(d[a[i]],i);
int l=0,r=1e15;
while(l+1<r){
int m=(l+r)/2;
vec<vec<int>>dp(n+1,vec<int>(p+1,1e15));
dp[0][0]=0;
for(int i=1;i<=n;i++){
int x=d[*(lower_bound(all(a),a[i]-2*m+1))];
int y=d[*(lower_bound(all(a),a[i]-m+1))];
// cout<<i<<' '<<x<<' '<<y<<endl;
for(int j=0;j<=p;j++){
dp[i][j]=dp[x-1][j]+1;
if(j!=0) dp[i][j]=min(dp[i][j],dp[y-1][j-1]);
}
}
bool f=0;
for(int j=0;j<=p;j++){
if(dp[n][j]<=q) f=1;
}
if(f) r=m;
else l=m;
// break;
}
cout<<r<<endl;
}
signed main(){
// freopen("","r",stdin);
// freopen("","w",stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cout<<fixed<<setprecision(20);
// cin>>itera;
for(iter=1;iter<=itera;iter++) solve();
}
