#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
int n;
int a[N];
bool can(long long x) {
  long long last = -1, used = 0;
  x *= 2;
  for (long long i = 0; i < n; i++) {
    if (last < a[i]) {
      last = a[i] + x;
      used++;
    }
  }
  return used <= 3;
}
unsigned long long bin() {
  unsigned long long l = 0, mid, r = 4e9;
  while (r - l > 0) {
    mid = (l + r) / 2;
    if (can(mid))
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    a[i] *= 2;
  }
  sort(a, a + n);
  long long d = bin();
  cout << fixed << setprecision(5) << d / 2.0 << endl;
  long long lastCovered = -1, used = 0;
  for (int i = 0; i < n; ++i) {
    if (a[i] > lastCovered) {
      printf("%lf ", (a[i] + d) / 2.0);
      lastCovered = a[i] + 2 * d;
      used++;
    }
  }
  while (used < 3) {
    cout << 0 << " ";
    used++;
  }
}
