Submission #987292

#	Time	Username	Problem	Language	Result	Execution time	Memory
987292		cig32	Rectangles (IOI19_rect)	C++17	72 / 100	5011 ms	471048 KiB

rect

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


const int MAXN = 2500;
int32_t upBad[MAXN][MAXN];
int32_t downBad[MAXN][MAXN];
int32_t leftBad[MAXN][MAXN];
int32_t rightBad[MAXN][MAXN];

int32_t up[MAXN][12][MAXN], down[MAXN][12][MAXN];
int32_t Left[MAXN][12][MAXN], Right[MAXN][12][MAXN];

int n,m;

int32_t dsu[MAXN * MAXN];

int set_of(int u) {
  if(dsu[u] == u) return u;
  return dsu[u] = set_of(dsu[u]);
}
void union_(int u, int v) {
  dsu[set_of(u)] = set_of(v);
}

int up_query(int i, int l, int r) {
  int k = 32 - __builtin_clz(r - l + 1) - 1;
  return max(up[i][k][l], up[i][k][r - (1<<k) + 1]);
}

int down_query(int i, int l, int r) {
  int k = 32 - __builtin_clz(r - l + 1) - 1;
  return min(down[i][k][l], down[i][k][r - (1<<k) + 1]);
}

int left_query(int i, int l, int r) {
  int k = 32 - __builtin_clz(r - l + 1) - 1;
  return max(Left[i][k][l], Left[i][k][r - (1<<k) + 1]);
}

int right_query(int i, int l, int r) {
  int k = 32 - __builtin_clz(r - l + 1) - 1;
  return min(Right[i][k][l], Right[i][k][r - (1<<k) + 1]);
}

int count_rectangles(std::vector<std::vector<int32_t> > a) {
	
  n = a.size(), m = a[0].size();

  int32_t mx = 0;
  for(int i=0; i<n; i++) {
    for(int j=0; j<m; j++) {
      mx = max(mx, a[i][j]);
      dsu[i * m + j] = i * m + j;
      rightBad[i][j] = m;
      downBad[i][j] = n;
      upBad[i][j] = -1;
      leftBad[i][j] = -1;
      for(int k=j+1; k<m; k++) {
        if(a[i][k] >= a[i][j]) {
          rightBad[i][j] = k; break;
        }
      }
      for(int k=j-1; k>=0; k--) {
        if(a[i][k] >= a[i][j]) {
          leftBad[i][j] = k; break;
        }
      }
      for(int k=i+1; k<n; k++) {
        if(a[k][j] >= a[i][j]) {
          downBad[i][j] = k; break;
        }
      }
      for(int k=i-1; k>=0; k--) {
        if(a[k][j] >= a[i][j]) {
          upBad[i][j] = k; break;
        }
      }
    }
  }
  
  if(mx == 1) {
    for(int i=0; i+1<n; i++) {
      for(int j=0; j+1<m; j++) {
        if(a[i][j] == 0 && a[i][j+1] == 0) union_(i*m + j, i*m + j + 1);
        if(a[i][j] == 0 && a[i+1][j] == 0) union_(i*m + j, (i+1)*m + j);
      }
    }

    vector<int> ll[n * m];
    for(int i=0; i<n*m; i++) ll[set_of(i)].push_back(i);
    int ans = 0;
    for(int i=0; i<n*m; i++) {
      if(ll[i].size()) {
        int r = ll[i][0] / m, c = ll[i][0] % m;
        if(a[r][c] == 1) continue;
        int u, d, l;
        u = l = 1e9, d = r = -1;
        for(int x: ll[i]) {
          u = min(u, x / m);
          d = max(d, x / m);
          l = min(l, x % m);
          r = max(r, x % m);
        }
        if((d - u + 1) * (r - l + 1) == ll[i].size() && u > 0 && l > 0 && d + 1 < n && r + 1 < m) {
          ans++;
        }
      }
    }
    return ans;
  }
  for(int i=0; i<n; i++) {
    for(int j=0; j<m; j++) {
      Left[j][0][i] = leftBad[i][j];
      Right[j][0][i] = rightBad[i][j];
      up[i][0][j] = upBad[i][j];
      down[i][0][j] = downBad[i][j];
    }
  }

  for(int k=1; k<12; k++) {
    for(int i=0; i<n; i++) {
      for(int j=0; j+(1<<k)-1<m; j++) {
        up[i][k][j] = max(up[i][k-1][j], up[i][k-1][j+(1<<(k-1))]);
        down[i][k][j] = min(down[i][k-1][j], down[i][k-1][j+(1<<(k-1))]);
      }
    }
    for(int i=0; i<m; i++) {
      for(int j=0; j+(1<<k)-1<n; j++) {
        Left[i][k][j] = max(Left[i][k-1][j], Left[i][k-1][j+(1<<(k-1))]);
        Right[i][k][j] = min(Right[i][k-1][j], Right[i][k-1][j+(1<<(k-1))]);
      }
    }
  }
  
  int ans = 0;
  for(int len=1; len<=n-2; len++) {
    for(int i=1; i+len-1<=n-2; i++) {
      int sto[m];
      for(int x=0; x<m; x++) sto[x] = -1;
      for(int x=1; x+1<m; x++) {
        int u, d, l, r;
        bool alive;
        u = i, d = i + len - 1;
        // as left
        l = x, r = right_query(x - 1, u, d) - 1;
        sto[l] = r;
        if(u <= d && l <= r && l > 0 && r + 1 < m) {
          alive = 1;
          alive &= (right_query(l - 1, u, d) > r);
          alive &= (left_query(r + 1, u, d) < l);
          alive &= (down_query(u - 1, l, r) > d);
          alive &= (up_query(d + 1, l, r) < u);
          ans += alive;
          //if(alive) cout << "u = " << u << ", d = " << d << ", l = " << l << ", r = "<<r<<"\n";
        }
        // as right
        l = left_query(x + 1, u, d) + 1, r = x;
        
        if(u <= d && l <= r && sto[l] != r && l > 0 && r + 1 < m) {
          alive = 1;
          alive &= (right_query(l - 1, u, d) > r);
          alive &= (left_query(r + 1, u, d) < l);
          alive &= (down_query(u - 1, l, r) > d);
          alive &= (up_query(d + 1, l, r) < u);
          ans += alive;
          //if(alive) cout << "u = " << u << ", d = " << d << ", l = " << l << ", r = "<<r<<"\n";
        }
      }
    }
  }
  

  return ans;
}

/*
g++ -std=c++17 -O2 -o rect grader.cpp rect.cpp
./rect < input.txt

*/

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:107:38: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |         if((d - u + 1) * (r - l + 1) == ll[i].size() && u > 0 && l > 0 && d + 1 < n && r + 1 < m) {
      |            ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~

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