oj.uz

Submission #332528

# Submission time Handle Problem Language Result Execution time Memory
332528 2020-12-02T19:26:00 Z morato Odašiljači (COCI20_odasiljaci) C++17
70 / 70
 351 ms 620 KB 
/**
 *    author:  morato
 *    created: 02.12.2020 16:14:43
**/
#include <bits/stdc++.h>

using namespace std;

const int N = 1005;

double X[N], Y[N];
int p[N], rnk[N];
int n;

int find(int v) {
  return p[v] == v ? v : p[v] = find(p[v]);
}

void merge(int a, int b) {
  int x = find(a);
  int y = find(b);
  if (x != y) {
    if (rnk[x] > rnk[y]) swap(x, y);
    p[x] = y;
    if (rnk[x] == rnk[y]) rnk[y]++;
  }
}

double dist(int i, int j) {
  return sqrt((X[i] - X[j]) * (X[i] - X[j]) + (Y[i] - Y[j]) * (Y[i] - Y[j]));
}

bool check(double radius) {
  for (int i = 1; i <= n; i++) {
    p[i] = i;
    rnk[i] = 0;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      if (dist(i, j) <= 2 * radius) {
        merge(i, j);
      }
    }
  }
  set<int> st;
  for (int i = 1; i <= n; i++) {
    st.insert(find(i));
  }
  return (int) st.size() == 1;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> X[i] >> Y[i];
  }
  double l = 0.0, r = 1e10, best = 0.0;
  for (int i = 0; i < 100; i++) {
    double m = (l + r) / 2.0;
    if (check(m)) {
      best = m;
      r = m;
    } else {
      l = m;
    }
  }
  cout << setprecision(10) << fixed << best << '\n';
  return 0;
}

Subtask #1
70.0 / 70.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 2 ms 364 KB Output is correct
4 Correct 4 ms 364 KB Output is correct
5 Correct 5 ms 364 KB Output is correct
6 Correct 106 ms 364 KB Output is correct
7 Correct 106 ms 364 KB Output is correct
8 Correct 233 ms 364 KB Output is correct
9 Correct 351 ms 492 KB Output is correct
10 Correct 310 ms 620 KB Output is correct