Submission #937441

#	Time	Username	Problem	Language	Result	Execution time	Memory
937441		duckindog	Palembang Bridges (APIO15_bridge)	C++17	31 / 100	2035 ms	15992 KiB

bridge

//from duckindog wth depression
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include<bits/stdc++.h>

using namespace std;

const int N = 100'000 + 10;
int k, n;

long long bridge(vector<pair<int, int>> x) {
  int n = x.size();
  if (!n) return 0;
  set<int> pos;
  vector<int> a(n + 1), b(n + 1);
  for (int i = 1; i <= n; ++i) {
    a[i] = x[i - 1].first;
    b[i] = x[i - 1].second;
    pos.insert(a[i]); pos.insert(b[i]);
  }
  sort(a.begin(), a.end()); sort(b.begin(), b.end());

  vector<long long> da(n + 1), db(n + 1);
  for (int i = 1; i <= n; ++i) {
    da[i] = da[i - 1] + a[i];
    db[i] = db[i - 1] + b[i];
  }

  auto cal = [&](int i) {
    auto itA = upper_bound(a.begin(), a.end(), i) - a.begin() - 1,
         itB = upper_bound(b.begin(), b.end(), i) - b.begin() - 1;
    long long ret = 0;
    ret += 1ll * itA * i - da[itA] + da[n] - da[itA] - 1ll * i * (n - itA);
    ret += 1ll * itB * i - db[itB] + db[n] - db[itB] - 1ll * i * (n - itB);
    return ret;
  };

  long long ret = 1'000'000'000'000'000;

  for (const auto& i : pos) {
    if (i == *pos.begin()) continue;
    int l = *prev(pos.lower_bound(i));
    int r = i, it = l;
    while (l <= r) {
      int mid = l + r >> 1;
      if (cal(mid) >= cal(mid + 1)) l = it = mid + 1;
      else r = mid - 1;
    }
    ret = min(ret, cal(it));
  }
  if (n == 1) return abs(a[1] - b[1]);
  return ret;
}

pair<int, int> x[N];

int32_t main() {
  cin.tie(0)->sync_with_stdio(0);

  if (fopen("duck.inp", "r")) {
    freopen("duck.inp", "r", stdin);
    freopen("duck.out", "w", stdout);
  }
  cin >> k >> n;

  long long answer = 0;
  for (int i = 1; i <= n; ++i) {
    char A, B;
    cin >> A >> x[i].first >> B >> x[i].second;
    if (A != B) continue;
    answer += abs(x[i].first - x[i].second);
    i -= 1; n -= 1;
  }

  if (!n) {
    cout << answer << "\n";
    return 0;
  }

  if (k == 1) {
    cout << bridge(vector<pair<int, int>>(x + 1, x + n + 1)) + answer + n << "\n";
    return 0;
  }

  sort(x + 1, x + n + 1, [&](auto a, auto b) {
    return a.first + a.second < b.first + b.second;
  });

  long long ret = 1'000'000'000'000'000;
  for (int i = 1; i <= n; ++i) {
    vector<pair<int, int>> lt(x + 1, x + i + 1),
                           rt(x + i + 1, x + n + 1);
    ret = min(ret, bridge(lt) + bridge(rt));
  }

  cout << ret + answer + n << "\n";

}

Compilation message (stderr)

bridge.cpp: In function 'long long int bridge(std::vector<std::pair<int, int> >)':
bridge.cpp:46:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   46 |       int mid = l + r >> 1;
      |                 ~~^~~
bridge.cpp: In function 'int32_t main()':
bridge.cpp:62:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |     freopen("duck.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bridge.cpp:63:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     freopen("duck.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 9 / 9
• Subtask 4: 0 / 32
• Subtask 5: 0 / 37