Submission #891500

#TimeUsernameProblemLanguageResultExecution timeMemory
891500Muhammad_AneeqRectangles (IOI19_rect)C++17
10 / 100
304 ms10984 KiB
/*
بسم الله الرحمن الرحيم
Author:
                          (:Muhammad Aneeq:)
*/
#pragma GCC optimize("O2")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#include <vector>
#include <iostream>
using namespace std;
int const N=2600;
struct segt
{
  vector<int>a;
  int seg[4*N];
  segt(vector<int>&s)
  {
    a=s;
    build(1,0,a.size()-1);
  } 
  void build(int i,int st,int en)
  {
    if (st==en)
    {
      seg[i]=a[st];
      return;
    }
    int mid=(st+en)/2;
    build(i*2,st,mid);build(i*2+1,mid+1,en);
    seg[i]=max(seg[i*2],seg[i*2+1]);
  }
  int get(int i,int l,int r,int st,int en)
  {
    if (st>=l&&en<=r)
      return seg[i];
    if (st>r||en<l)
      return 0;
    int mid=(st+en)/2;
    return max(get(i*2,l,r,st,mid),get(i*2+1,l,r,mid+1,en));
  }
};
segt* St[2][N]={NULL};
long long count_rectangles(vector<vector<int>>a)
{
  int n=a.size(),m=a[0].size();
  for (int i=0;i<n;i++)
    St[0][i]=new segt(a[i]);
  for (int i=0;i<m;i++)
  {
    vector<int>z;
    for (int j=0;j<n;j++)
      z.push_back(a[j][i]);
    St[1][i]=new segt(z);
  }
  bool w=0;
  for (int i=0;i<n;i++)
  {
    for(int j=0;j<m;j++)
      if (a[i][j]>1)
        w=1;
  }
  if (w==0)
  {
    int pre[n+1][m+1]={};
    for (int i=1;i<=n;i++)
      for (int j=1;j<=m;j++)
        pre[i][j]=pre[i-1][j]+pre[i][j-1]-pre[i-1][j-1]+a[i-1][j-1];
    long long ans=0;
    for (int i=1;i<n-1;i++)
    {
      for (int j=1;j<m-1;j++)
      {
        if (a[i][j]==0&&a[i][j-1]==1&&a[i-1][j]==1)
        {
          int st=i,en=n;
          while (st+1<en)
          {
            int mid=(st+en)/2;
            if (pre[mid+1][j+1]-pre[mid+1][j]-pre[i][j+1]+pre[i][j]==0)
            {
              st=mid;
            }
            else
              en=mid;
          }
          if (st==n-1)
            continue;
          int k=st;
          st=j,en=m-1;
          while (st+1<en)
          {
            int mid=(st+en)/2;
            if (pre[k+1][mid+1]-pre[k+1][j]-pre[i][mid+1]+pre[i][j]==0)
              st=mid;
            else
              en=mid;
          }
          if (st==m-1)
            continue;
          int l=st;
          if (pre[k+1][l+1]-pre[i][l+1]-pre[k+1][j]+pre[i][j]==0)
            ans++;
        }
      }
    }
    return ans;
  }
  long long ans=0;
  for (int i=1;i<n-1;i++)
  {
    for (int j=1;j<m-1;j++)
    {
      for (int k=i;k<n-1;k++)
      {
        for (int l=j;l<m-1;l++)
        {
          bool w=0;
          for (int o=i;o<=k&&!w;o++)
          {
            int f=St[0][o]->get(1,j,l,0,m-1);
            if (f>=a[o][j-1]||f>=a[o][l+1])
              w=1;
          }
          for (int o=j;o<=l&&!w;o++)
          {
            int f=St[1][o]->get(1,i,k,0,n-1); 
            if (f>=a[i-1][o]||f>=a[k+1][o])
              w=1;
          }
          ans+=(!w);
        }
      }
    }
  }
  return ans;
}
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