#include "bits/stdc++.h"
using namespace std;
/*
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using ordered_set = tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>;
*/
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
using ll = long long;
const int mod = 1e9+7;
int n, p, q;
vector<int> v;
bool chk(int w) {
vector<vector<int>> dp(n, vector<int>(p+1));
int smol = 0, big = 0;
for (int i = 0; i < n; ++i) {
while (v[i] - v[smol] >= w) ++smol;
while (v[i] - v[big] >= 2*w) ++big;
if (big) dp[i][0] = dp[big-1][0] + 1;
else dp[i][0] = 1;
for (int j = 1; j <= p; ++j) {
if (smol == 0) dp[i][j] = 0;
else if (big == 0) dp[i][j] = min(dp[smol-1][j-1], 1);
else dp[i][j] = min(dp[smol-1][j-1], dp[big-1][j] + 1);
}
}
// for (int i = 0; i <= p; ++i) cerr << dp[n-1][i] << " ";
// cerr << '\n';
return dp[n-1][p] <= q;
}
void solve(int tc) {
cin >> n >> p >> q;
v.resize(n);
for (auto &x : v) cin >> x;
sort(all(v));
if (p+q >= n) {
cout << "1\n";
return;
}
int lo = 0, hi = 1e9+1;
while (lo < hi) {
int mid = lo + (hi - lo) / 2;
// cerr << "mid : " << mid << '\n';
if (chk(mid)) {
hi = mid;
} else {
lo = mid+1;
}
}
cout << hi << '\n';
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
int tc = 1;
//cin >> tc;
for (int i = 1; i <= tc; ++i) solve(i);
return 0;
}
