Submission #441786

#	Time	Username	Problem	Language	Result	Execution time	Memory
441786		peijar	Rectangles (IOI19_rect)	C++17	28 / 100	5054 ms	342596 KiB

rect

#include "rect.h"
#include <algorithm>
#include <bits/stdc++.h>
#define int long long
using namespace std;

bool seen[2500][2500];
int DX[] = {-1, 1, 0, 0};
int DY[] = {0, 0, -1, 1};
int nbLig, nbCol;
int maxLig, minLig, minCol, maxCol, nbVus;
vector<vector<signed>> val;

void dfs(int iLig, int iCol) {
  if (nbLig <= iLig or iLig < 0 or iCol < 0 or iCol >= nbCol or
      seen[iLig][iCol] or val[iLig][iCol])
    return;
  nbVus++;
  maxLig = max(maxLig, iLig);
  minLig = min(minLig, iLig);
  minCol = min(minCol, iCol);
  maxCol = max(maxCol, iCol);
  seen[iLig][iCol] = true;
  for (int d = 0; d < 4; ++d) {
    int col = iCol + DX[d];
    int lig = iLig + DY[d];
    dfs(lig, col);
  }
}

int solveBinary() {
  int ret = 0;

  for (int iLig = 0; iLig < nbLig; ++iLig)
    for (int iCol = 0; iCol < nbCol; ++iCol)
      if (!seen[iLig][iCol] and !val[iLig][iCol]) {
        minLig = maxLig = iLig;
        minCol = maxCol = iCol;
        nbVus = 0;
        dfs(iLig, iCol);
        ret += nbVus == (maxLig - minLig + 1) * (maxCol - minCol + 1) and
               maxLig < nbLig - 1 and minLig > 0 and minCol > 0 and
               maxCol < nbCol - 1;
      }
  return ret;
}

int count_rectangles(vector<vector<signed>> a) {
  val = a;
  nbLig = a.size(), nbCol = a[0].size();
  bool isBinary = true;
  for (auto v : a)
    for (auto w : v)
      isBinary &= w < 2;
  if (isBinary)
    return solveBinary();
  vector<vector<int>> down(nbLig, vector<int>(nbCol));
  vector<vector<int>> up(nbLig, vector<int>(nbCol));
  vector<vector<int>> right(nbLig, vector<int>(nbCol));
  vector<vector<int>> left(nbLig, vector<int>(nbCol));

  for (int col = 0; col < nbCol; ++col) {
    for (int iLig = nbLig - 1; iLig >= 0; --iLig) {
      int nxt = iLig + 1;
      while (nxt < nbLig and a[iLig][col] > a[nxt][col])
        nxt = down[nxt][col];
      down[iLig][col] = nxt;
    }

    for (int iLig = 0; iLig < nbLig; ++iLig) {
      int nxt = iLig - 1;
      while (nxt >= 0 and a[iLig][col] > a[nxt][col])
        nxt = up[nxt][col];
      up[iLig][col] = nxt;
    }
  }

  for (int lig = 0; lig < nbLig; ++lig) {
    for (int iCol = nbCol - 1; iCol >= 0; --iCol) {
      int nxt = iCol + 1;
      while (nxt < nbCol and a[lig][iCol] > a[lig][nxt])
        nxt = right[lig][nxt];
      right[lig][iCol] = nxt;
    }
    for (int iCol = 0; iCol < nbCol; ++iCol) {
      int nxt = iCol - 1;
      while (nxt >= 0 and a[lig][iCol] > a[lig][nxt])
        nxt = left[lig][nxt];
      left[lig][iCol] = nxt;
    }
  }
  int sol = 0;
  for (int lig1 = 0; lig1 < nbLig; ++lig1)
    for (int lig2 = lig1 + 2; lig2 < nbLig; ++lig2)
      for (int col1 = 0; col1 < nbCol; ++col1)
        for (int col2 = col1 + 2; col2 < nbCol; ++col2) {
          bool ok = true;
          for (int i = lig1 + 1; i < lig2; ++i)
            ok &= right[i][col1] >= col2 and left[i][col2] <= col1;
          for (int i = col1 + 1; i < col2; ++i)
            ok &= up[lig2][i] <= lig1 and down[lig1][i] >= lig2;
          sol += ok;
        }

  return sol;
}

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 0 / 12
• Subtask 4: 0 / 22
• Subtask 5: 0 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28