Submission #304118

#	Time	Username	Problem	Language	Result	Execution time	Memory
304118		Fdg	Counting Mushrooms (IOI20_mushrooms)	C++14	80.14 / 100	20 ms	736 KiB

mushrooms

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include "mushrooms.h"

using namespace std;

const int VAL = 144;

vector<int> a, b, missing;

map<int, vector<int>> diff, eq;
set<int> found;

void nextPos(const vector<int>& v, int& pos) {
  while (pos < (int) v.size()) {
    if (found.count(v[pos])) {
      ++pos;
    } else break;
  }
}

void process(int x, bool isA) {
  if (found.count(x)) return;
  found.insert(x);

  if (isA) a.push_back(x);
  else b.push_back(x);

  if (diff.count(x))
    for (int val : diff[x]) {
      process(val, !isA);
    }

  if (eq.count(x))
    for (int val : eq[x]) {
      process(val, isA);
    }
}

int count_mushrooms(int n) {
  a.clear(); b.clear(); diff.clear(); found.clear(); missing.clear();

  srand(time(NULL));
  vector<int> v;
  for (int i = 0; i < n; ++i)
    v.push_back(i);
  for (int it = 0; it < 2; ++it) {
    random_shuffle(v.begin(), v.end());
    use_machine(v);
  }

  v.clear();
  for (int i = 1; i < n; ++i)
    v.push_back(i);
  random_shuffle(v.begin(), v.end());

  int ans = 0, pos = 0;

  bool doNextSimple = false;

  a.push_back(0); found.insert(0);
  while (a.size() < VAL && b.size() < VAL && pos < (int) v.size()) {
    if (a.size() > 1) {
      vector<int> arr;
      nextPos(v, pos);
      if (pos < (int) v.size()) {
        arr.push_back(v[pos]), ++pos;
        arr.push_back(a[0]);
      }
      nextPos(v, pos);
      if (pos < (int) v.size()) {
        arr.push_back(v[pos]), ++pos;
        arr.push_back(a[1]); 
      }
      // if (!doNextSimple) {
      //   nextPos(v, pos);
      //   if (pos < (int) v.size()) arr.push_back(v[pos]), ++pos;
      // }

      doNextSimple = false;
      int ret = use_machine(arr);
      if (arr.size() == 2) {
        if (ret == 1) {
          process(arr[0], false);
        } else {
          process(arr[0], true);
        }
      } else if (arr.size() == 4) {
        if (ret == 3) {
          process(arr[0], false);
          process(arr[2], false);
        } else if (ret == 2) {
          process(arr[0], true);
          process(arr[2], false);
        } else if (ret == 1) {
          process(arr[0], false);
          process(arr[2], true); 
        } else {
          process(arr[0], true);
          process(arr[2], true);
        }
      } else if (arr.size() == 5) {
        if (ret == 4) {
          process(arr[0], false);
          process(arr[2], false);
          process(arr[4], false);
        } else if (ret == 3) {
          process(arr[2], false);
          diff[arr[0]].push_back(arr[4]);
          diff[arr[4]].push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[0];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else if (ret == 2) {
          diff[arr[0]].push_back(arr[2]);
          diff[arr[2]].push_back(arr[0]);
          diff[arr[4]].push_back(arr[2]);
          diff[arr[2]].push_back(arr[4]);
          eq[arr[0]].push_back(arr[4]);
          eq[arr[4]].push_back(arr[0]);
          missing.push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[2];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else if (ret == 1) {
          process(arr[2], true);
          diff[arr[0]].push_back(arr[4]);
          diff[arr[4]].push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[0];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else {
          process(arr[0], true);
          process(arr[2], true);
          process(arr[4], true);
        }
      }
    } else if (b.size() > 1) {
      vector<int> arr;
      nextPos(v, pos);
      if (pos < (int) v.size()) {
        arr.push_back(v[pos]), ++pos;
        arr.push_back(b[0]);
      }
      nextPos(v, pos);
      if (pos < (int) v.size()) {
        arr.push_back(v[pos]), ++pos;
        arr.push_back(b[1]); 
      }
      // if (!doNextSimple) {
      //   nextPos(v, pos);
      //   if (pos < (int) v.size()) arr.push_back(v[pos]), ++pos;
      // }

      doNextSimple = false;
      int ret = use_machine(arr);
      if (arr.size() == 2) {
        if (ret == 1) {
          process(arr[0], true);
        } else {
          process(arr[0], false);
        }
      } else if (arr.size() == 4) {
        if (ret == 3) {
          process(arr[0], true);
          process(arr[2], true);
        } else if (ret == 2) {
          process(arr[0], false);
          process(arr[2], true);
        } else if (ret == 1) {
          process(arr[0], true);
          process(arr[2], false); 
        } else {
          process(arr[0], false);
          process(arr[2], false);
        }
      } else if (arr.size() == 5) {
        if (ret == 4) {
          process(arr[0], true);
          process(arr[2], true);
          process(arr[4], true);
        } else if (ret == 3) {
          process(arr[2], true);
          diff[arr[0]].push_back(arr[4]);
          diff[arr[4]].push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[0];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else if (ret == 2) {
          diff[arr[0]].push_back(arr[2]);
          diff[arr[2]].push_back(arr[0]);
          diff[arr[4]].push_back(arr[2]);
          diff[arr[2]].push_back(arr[4]);
          eq[arr[0]].push_back(arr[4]);
          eq[arr[4]].push_back(arr[0]);
          missing.push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[2];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else if (ret == 1) {
          process(arr[2], false);
          diff[arr[0]].push_back(arr[4]);
          diff[arr[4]].push_back(arr[0]);
          missing.push_back(arr[4]);
          --pos;
          v[pos] = arr[0];
          if (pos + 1 < (int) v.size()) swap(v[pos], v[pos + 1]);
          doNextSimple = true;
        } else {
          process(arr[0], false);
          process(arr[2], false);
          process(arr[4], false);
        }
      }
    } else {
      vector<int> arr = {a[0]};
      nextPos(v, pos);
      if (pos < (int) v.size()) arr.push_back(v[pos]), ++pos;
      else break;

      doNextSimple = false;
      int ret = use_machine(arr);
      if (ret & 1) {
        process(arr[1], false);
      } else {
        process(arr[1], true);
      }
    }
  }

  ans = a.size();

  // if (a.size() + b.size() != n) exit(-1);

  for (int x : missing) {
    if (!found.count(x))
      v.push_back(x);
  }

  if (a.size() >= b.size()) {
    while (pos < (int) v.size()) {
      vector<int> arr;
      int used = 0;
      for (int i = 0; i < (int) a.size(); ++i) {
        arr.push_back(a[i]);
        nextPos(v, pos);
        if (pos < (int) v.size()) arr.push_back(v[pos]), ++pos, ++used;
        else break;
      }
      int ret = use_machine(arr);
      int diff = (ret / 2) + (ret & 1);
      ans += used - diff;
    }
  } else {
    while (pos < (int) v.size()) {
      vector<int> arr;
      int used = 0;
      for (int i = 0; i < (int) b.size(); ++i) {
        arr.push_back(b[i]);
        nextPos(v, pos);
        if (pos < (int) v.size()) arr.push_back(v[pos]), ++pos, ++used;
        else break;
      }
      int ret = use_machine(arr);
      int diff = (ret / 2) + (ret & 1);
      ans += diff;
    }
  }

  return ans;
}

// int count_mushrooms(int n) {
//   int ans = 1;
//   for (int i = 1; i < n; i += 2) {
//     vector<int> v;
//     if (i + 1 < n) v = {i, 0, i + 1};
//     else v = {i, 0};
//     int ret = use_machine(v);
//     ans += (v.size() - 1) - ret;
//   }
//   return ans;
// }

// int main() {
//   ios::sync_with_stdio(false);

//   return 0; 
// }

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:62:8: warning: variable 'doNextSimple' set but not used [-Wunused-but-set-variable]
   62 |   bool doNextSimple = false;
      |        ^~~~~~~~~~~~

• Subtask 1: 80.1418 / 100