Submission #234313

#	Time	Username	Problem	Language	Result	Execution time	Memory
234313		UserIsUndefined	Rectangles (IOI19_rect)	C++14	0 / 100	5 ms	512 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>



int presum[3000][3000];


using namespace std;

long long count_rectangles(std::vector<std::vector<int> > a) {

    int n = a.size();
    int m = a[0].size();

    long long ans = 0;
    /*
    for (int i = 1 ; i < n - 1 ; i++){
        for (int j = 1 ; j < m - 1 ; j++){
            int limitTol = n - 1;
            int limitArad = m - 1;

            for (int tol = 1 ; tol + i - 1 < limitTol ; tol++){
                for (int arad = 1 ; arad + j - 1 < limitArad ; arad++){
                    int r1 = i, r2 = i + tol, c1 = j, c2 = j + arad;
                    bool ok = false;
                    for (int row = r1 ; row < r2 ; row++){
                        for (int cal = c1 ; cal < c2 ; cal++){
                            if (a[row][cal] < a[r1 - 1][cal] && a[row][cal] < a[row][c1 - 1] && a[row][cal] < a[r2][cal] && a[row][cal] < a[row][c2]){
                                continue;
                            }
                            else {
                                if (a[row][cal] >= a[r1 - 1][cal] || a[row][cal] >= a[row][c1 - 1])limitArad = cal;
                                ok = true;
                                break;
                            }
                        }
                        if (ok)break;
                    }


                    if (ok == false)ans++;


                }
            }
        }
    }

    */








    vector<pair<int,int>> zeros;


    for (int i = 0 ; i < n ; i++){
        for (int j = 0 ; j < m ; j++){
            if (j == 0)presum[i][j] = a[i][j];
            else presum[i][j] = presum[i][j-1] + a[i][j];
        }
    }




    for (int j = 0 ; j < m ; j++){
        for (int i = 0 ; i < n ; i++){
            if (i == 0)presum[i][j] = presum[i][j];
            else presum[i][j] = presum[i-1][j] + presum[i][j];
        }
    }



    for (int i = 1 ; i < n - 1 ; i++){
        for (int j = 1 ; j < m - 1; j++){
            if (a[i][j] == 0){
                zeros.push_back({i,j});
            }
        }
    }







    for (int i = 0 ; i < zeros.size(); i++){
        for (int j = i  ; j < zeros.size() ; j++){

            if (zeros[j].first < zeros[i].first || zeros[j].second < zeros[i].second)continue;

            int big = presum[zeros[j].first][zeros[j].second];
            int small = presum[zeros[i].first - 1][zeros[i].second - 1];
            int first = presum[zeros[j].first][zeros[i].second - 1];
            int second = presum[zeros[i].first-1][zeros[j].second];
//            cout << "from " << "(" << zeros[i].first << "," << zeros[i].second << ") to (" << zeros[j].first << "," << zeros[j].second << ")" <<endl;

            int sum = big - first - second + small;
//             cout << "sum = " << sum << endl;
            if (sum == 0)ans++;

        }
    }



    return ans;

}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:95:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0 ; i < zeros.size(); i++){
                      ~~^~~~~~~~~~~~~~
rect.cpp:96:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = i  ; j < zeros.size() ; j++){
                           ~~^~~~~~~~~~~~~~

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