#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
void minSelf(int &x, int y) {
if (y < x) {
x = y;
}
}
void testCase() {
int n, p, q;
cin >> n >> p >> q;
vector<int> a(n + 1);
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
if (p >= n || q >= n) {
cout << "1\n";
return;
}
auto check = [&](const int &x) -> bool {
vector<vector<int>> dp(n + 1, vector<int>(p + 1, INF));
int ptr1 = 1, ptr2 = 1;
dp[0][0] = 0;
for (int i = 1; i <= n; ++i) {
while (a[i] - a[ptr1] >= x) {
ptr1 += 1;
}
while (a[i] - a[ptr2] >= 2 * x) {
ptr2 += 1;
}
for (int j = 0; j <= p; ++j) {
if (j >= 1) {
minSelf(dp[i][j], dp[ptr1 - 1][j - 1]);
}
minSelf(dp[i][j], dp[ptr2 - 1][j] + 1);
}
}
for (int i = 0; i <= p; ++i) {
if (dp[n][i] <= q) {
return true;
}
}
return false;
};
sort(a.begin() + 1, a.end());
int l = 1, r = (a[n] - a[1] + 2) / 2;
while (l <= r) {
int mid = (l + r) / 2;
if (check(mid)) {
r = mid - 1;
} else {
l = mid + 1;
}
}
cout << r + 1 << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int tests = 1;
for (int tc = 0; tc < tests; ++tc) {
testCase();
}
return 0;
}
