Submission #143079

#	Time	Username	Problem	Language	Result	Execution time	Memory
143079		model_code	Arranging Shoes (IOI19_shoes)	C++17	30 / 100	124 ms	14888 KiB

shoes

#include "shoes.h"

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

namespace testcaseCheck {

const int SUBTASK = 2;

bool permutationsOfShoes(vector<int> S, int N) {
  vector<int> V;
  for (int i = 1; i <= N; ++i) {
    V.push_back(-i);
    V.push_back(i);
  }

  sort(S.begin(), S.end());
  sort(V.begin(), V.end());
  for (int i = 0; i < 2 * N; ++i) {
    if (S[i] != V[i]) {
      return false;
    }
  }

  return true;
}

void run(std::vector<int> S) {
  assert(1 <= SUBTASK && SUBTASK <= 6);

  assert(S.size() % 2 == 0);
  int N = S.size() / 2;
  assert(1 <= N && N <= 100000);
  
  map<int, int> sizeToOccurences;
  for (int s : S) {
    sizeToOccurences[abs(s)] += s / abs(s);
  }
  for (pair<int, int> occurences : sizeToOccurences) {
    assert(occurences.second == 0);
  }

  if (SUBTASK == 1) {
    assert(N == 1);
  }

  if (SUBTASK == 2) {
    assert(N <= 8);
  }

  if (SUBTASK == 3) {
    for (int s : S) {
      assert(abs(s) == abs(S[0]));
    }
  }

  if (SUBTASK == 4) {
    for (int i = 0; i < N; ++i) {
      assert(abs(S[i]) == S[i + N]);
    }
  }

  if (SUBTASK == 5) {
    assert(N <= 1000);
  }
}


}  // namespace testcaseCheck

long long count_swaps(std::vector<int> S) {
  testcaseCheck::run(S);  
  
  vector<int> sizes;
  for (int s : S) {
    if (s > 0) {
      sizes.push_back(s);
    }
  }

  int answer = INT_MAX;
  sort(sizes.begin(), sizes.end());
  do {
    int res = 0;
    vector<int> currentOrder = S;
    vector<int> expectedOrder;
    for (int i = 0; i < sizes.size(); ++i) {
      expectedOrder.push_back(-sizes[i]);
      expectedOrder.push_back(sizes[i]);
    }

    for (int i = 0; i < expectedOrder.size(); ++i) {
      for (int j = i; j < currentOrder.size(); ++j) {
        if (currentOrder[j] == expectedOrder[i]) {
          while (i != j) {
            swap(currentOrder[j], currentOrder[j - 1]);
            --j;
            ++res;
          }
          break;
        }
      }
    }

    answer = min(answer, res);
  } while (next_permutation(sizes.begin(), sizes.end()));

  return answer;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:87:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < sizes.size(); ++i) {
                     ~~^~~~~~~~~~~~~~
shoes.cpp:92:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < expectedOrder.size(); ++i) {
                     ~~^~~~~~~~~~~~~~~~~~~~~~
shoes.cpp:93:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for (int j = i; j < currentOrder.size(); ++j) {
                       ~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15