#include <bits/stdc++.h>
#define int long long
using namespace std;
ostream &operator <<(ostream &out, vector <int> val) {
for (auto v : val) {
out << v << ' ';
}
return out;
}
bool check(vector <int> &val, int w, int n, int p, int q) {
vector <vector <int>> dp(n + 1, vector <int> (p + 1, 2e9));
dp[0][0] = 0;
int ind1 = 0, ind2 = 0;
for (int i = 0; i < n; ++i) {
while (val[i] - val[ind1] + 1 > w) {
++ind1;
}
for (int j = 1; j <= p; ++j) {
dp[i + 1][j] = min(dp[i + 1][j], dp[ind1][j - 1]);
}
while (val[i] - val[ind2] + 1 > 2 * w) {
++ind2;
}
for (int j = 0; j <= p; ++j) {
dp[i + 1][j] = min(dp[i + 1][j], dp[ind2][j] + 1);
}
}
return *min_element(dp.back().begin(), dp.back().end()) <= q;
}
void solve() {
int n, p, q;
cin >> n >> p >> q;
vector <int> val(n);
for (int i = 0; i < n; ++i) {
cin >> val[i];
}
if (p + q >= n) {
cout << 1 << '\n';
return;
}
sort(val.begin(), val.end());
int l = 0, r = 2e9;
while (r - l > 1) {
int med = (l + r) / 2;
if (check(val, med, n, p, q)) {
r = med;
} else {
l = med;
}
}
cout << r << '\n';
}
signed main() {
cin.tie(0);
ios::sync_with_stdio(false);
int t = 1;
// cin >> t;
for (int i = 0; i < t; ++i) {
solve();
}
}
