Submission #415089

#	Time	Username	Problem	Language	Result	Execution time	Memory
415089		schse	Mechanical Doll (IOI18_doll)	C++17	12 / 100	192 ms	28260 KiB

doll

#include "doll.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
using namespace std;

struct node
{
  vector<int> follow;
  set<int> options;
};

vector<node> g;

vector<int> C, X, Y;
int mx = 2;
vector<bool> tree((1 << 18) + 5, true);

void rec(int index, int value)
{
  if (index >= mx / 2)
  {
    if (tree[index])
      X[index - 1] = value;
    else
      Y[index - 1] = value;
  }
  else if (tree[index])
    rec(index * 2, value);
  else
    rec(index * 2 + 1, value);
  tree[index] = !tree[index];
}

void create_circuit(int M, std::vector<int> A)
{
  int N = A.size();
  A.push_back(0);
  while (N >= (mx = mx * 2) * 2)
    ;

  { // built graph
    g.resize(M + 1);
    g[0].follow.push_back(A[0]);
    g[0].options.insert(A[0]);
    for (int i = 1; i < N; i++)
    {
      g[A[i - 1]].follow.push_back(A[i]);
      g[A[i - 1]].options.insert(A[i]);
    }
  }

  C.resize(M + 1);
  fill(C.begin(), C.end(), -1);
  C[0] = A[0];

  // eliminate unnecessary

  int toeliminate = N - mx;
  for (int i = 1; i < M + 1; i++)
  {
    if (g[i].options.size() == 1 && toeliminate > 0)
    {
      toeliminate -= g[i].follow.size();
      C[i] = g[i].follow.back();
    }
    else if (g[i].options.empty())
      C[i] = 0;
  }

  if (toeliminate > 0)
  {
    for (int i = 0; i < M + 1; i++)
    {
      if (g[i].follow.size() == 2)
      {
        toeliminate -= 2;
        X.push_back(g[i].follow[0]);
        Y.push_back(g[i].follow[1]);
        C[i] = -X.size();
      }
      else if (g[i].options.size() == 2 && g[i].follow.size() % 2 == 2)
      {
        bool b = true;
        for (int e = 0; e < g[i].follow.size(); e++)
          b &= (g[i].follow[e] == g[i].follow[e % 2]);
        if (b)
        {
          toeliminate -= 2;
          X.push_back(g[i].follow[0]);
          Y.push_back(g[i].follow[1]);
          C[i] = -X.size();
        }
      }
      if (toeliminate <= 0)
        break;
    }
  }

  int offset = X.size();
  for (int i = 0; i < mx - 1; i++)
  {
    X.push_back(-offset - 1);
    Y.push_back(-offset - 1);
  }
  for (int i = 1; i < mx / 2; i++)
  {
    X[i - 1 + offset] = i * -2 - offset;
    Y[i - 1 + offset] = i * -2 - 1 - offset;
  }

  bool b = false;

  int last = -1;
  for (int i = 1; i < N + 1; i++)
  {
    if (!b && C[A[i - 1]] == -1)
    {
      last = A[i];
      b = true;
    }
    else if (C[A[i - 1]] == -1)
    {

      rec(1, last);
      last = A[i];
    }
  }

  Y[Y.size() - 1] = last;
  if (b)
    answer(C, X, Y);
  else
    answer(C, {}, {});
}

Compilation message (stderr)

doll.cpp: In function 'void create_circuit(int, std::vector<int>)':
doll.cpp:86:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |         for (int e = 0; e < g[i].follow.size(); e++)
      |                         ~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 2 / 2
• Subtask 2: 0 / 4
• Subtask 3: 0 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 18
• Subtask 6: 0 / 56