Submission #278219

#	Time	Username	Problem	Language	Result	Execution time	Memory
278219		erray	Watching (JOI13_watching)	C++17	0 / 100	586 ms	15564 KiB

watching

// author: erray
#include<bits/stdc++.h>
 
using namespace std;

template<typename T, typename F> string to_string(pair<T, F> p);
string to_string(string s) {
  return '"' + s + '"';
}
string to_string(char c) {
  return (string) "'" + c + "'";
}
string to_string(const char* p) {
  return to_string((string) p);
}
string to_string(bool B) {
  return (B ? "true" : "false");
}
string to_string(vector<bool> v) {
  string res = "{";
  for (int i = 0; i < (int) v.size(); ++i) {
    if ((int) res.size() > 1) res += ", ";
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template<size_t T> string to_string(bitset<T> bs) {
  return bs.to_string();
}
template<typename T> string to_string(T v) {
  string res = "{";
  for (auto& el : v) {
    if ((int) res.size() > 1) res += ", ";
    res += to_string(el);
  }
  res += "}";
  return res;
}
template<typename T, typename F> string to_string(pair<T, F> p) {
  return '(' + to_string(p.first) + ", " + to_string(p.second) + ')';
}
void debug_out() {
  cerr << endl;
}
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#ifdef DEBUG
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:" , debug_out(__VA_ARGS__)
#else
#define debug(...) (void) 37
#endif
 
int main () {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, p, q;
  cin >> n >> p >> q;
  if (p + q >= n) return cout << 1, 0;
  vector<int> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a.begin(), a.end());
  auto check = [&](int l) {
    vector<vector<int>> dp(n, vector<int>(p + 1, INT_MAX));
    auto get = [&](int x, int y) {
      if (y > p) return (int) 1e9;
      if (x == n) return 0;
      return dp[x][y];
    };
    int p1 = n - 1, p2 = n - 1;
    for (int i = n - 1; i >= 0; --i) {
      while (p1 > 0 && a[p1] > a[i] + l) --p1;
      while (p2 > 0 && a[p2] > a[i] + 2 * l) --p2;
      for (int j = 0; j <= p; ++j) {
        dp[i][j] = get(p1 + 1, j + 1);
        dp[i][j] = min(dp[i][j], get(p2 + 1, j) + 1);
      }
    }
    return dp[0][0] <= q;
  };
  int s = 1, e = (int) 1e9;
  while (s != e) {
    int mid = (s + e) >> 1;
    if (check(mid)) e = mid;
    else s = mid + 1;    
    debug(s, e);
  }
  cout << s + 1 << '\n';
}

• Subtask 1: 0 / 50
• Subtask 2: 0 / 50