Submission #726878

#	Time	Username	Problem	Language	Result	Execution time	Memory
726878		LittleFlowers__	Fun Tour (APIO20_fun)	C++17	47 / 100	428 ms	106532 KiB

fun

#include "fun.h"

#include <bits/stdc++.h>

using namespace std;

string to_string(string s) {
  return '"' + s + '"';
}
 
string to_string(const char* s) {
  return to_string((string) s);
}
 
string to_string(bool b) {
  return (b ? "true" : "false");
}
 
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
 
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
 
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 LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

mt19937 rng(101202);
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r) {
  if (l > r) { cerr << l << " " << r << "\n"; }
  return l + rng() % (r - l + 1);
}

const int N = 100010;

set<pair<int, int>> children[N * 4];

vector<int> createFunTour(int n, int q) {
  if (n <= 500) {
    vector<vector<int>> distance(n, vector<int>(n));
    vector<pair<int, int>> edges;
    vector<bool> visited(n);
    for (int i = 0; i < n; ++i) for (int j = i + 1; j < n; ++j) {
      distance[i][j] = distance[j][i] = hoursRequired(i, j);
      edges.push_back({i, j});
      edges.push_back({j, i});
    }
  
    sort(edges.begin(), edges.end(), [&](pair<int, int> x, pair<int, int> y) {
      return distance[x.first][x.second] > distance[y.first][y.second];
    });
  
    int currentVertex = edges[0].first, fun = n;
    visited[currentVertex] = true;
    vector<int> answer = {currentVertex};
    for (int i = 1; i < n; ++i) {
      bool found = false;
      for (const auto [x, y] : edges) {
        if (x != currentVertex || !visited[x] || visited[x] && visited[y] || fun < distance[x][y]) continue;
        answer.push_back(currentVertex = y);
        visited[y] = true;
        found = true;
        break;
      }
      assert(found);
    }
  
    return answer;
  }

  function<void(int)> build = [&](int s) {
    if (s >= n) return;
    build(2 * s + 1); build(2 * s + 2);
    children[s].insert({0, s});
    for (const auto &[c, v] : children[2 * s + 1]) children[s].insert({c + 1, v});
    for (const auto &[c, v] : children[2 * s + 2]) children[s].insert({c + 1, v});
  };

  build(0);

  vector<bool> visited(n);

  function getSubtree = [&](int u) -> pair<int, int> {
    while (children[u].size() && visited[children[u].rbegin()->second]) children[u].erase(*children[u].rbegin());
    return children[u].size() ? *children[u].rbegin() : make_pair(0, -1);
  };

  function getSubtree_Left = [&](int u) -> pair<int, int> {
    return getSubtree(u * 2 + 1);
  };

  function getSubtree_Right = [&](int u) -> pair<int, int> {
    return getSubtree(u * 2 + 2);
  };

  int currentVertex = 0; while (currentVertex * 2 + 1 < n) currentVertex = currentVertex * 2 + 1;
  visited[currentVertex] = true;
  vector<int> answer = {currentVertex};
  for (int i = 1; i < n; ++i) {
    pair<
      int, // distance
      int  // vertex
    > currentBest;
    currentBest = getSubtree(currentVertex);
    for (int u = currentVertex, level = 1; u > 0; u = (u - 1) / 2, level += 1) {
      int p = (u - 1) / 2;

      auto thisBest_ = u == p * 2 + 1 ? getSubtree_Right(p) : getSubtree_Left(p);
      pair<int, int> thisBest = {0, -1};
      if (!visited[p]) thisBest = {level, p};
      if (thisBest_.second != -1) thisBest = {thisBest.first + thisBest_.first, thisBest_.second};
      if (thisBest > currentBest) currentBest = thisBest;
    }
    visited[currentVertex = currentBest.second] = true;
    answer.push_back(currentVertex);
  }

  return answer;
}

Compilation message (stderr)

fun.cpp: In function 'std::vector<int> createFunTour(int, int)':
fun.cpp:85:61: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   85 |         if (x != currentVertex || !visited[x] || visited[x] && visited[y] || fun < distance[x][y]) continue;
      |                                                  ~~~~~~~~~~~^~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 34