Submission #878108

#	Time	Username	Problem	Language	Result	Execution time	Memory
878108		AI_2512	Chessboard (IZhO18_chessboard)	C++17	31 / 100	849 ms	262144 KiB

chessboard

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

vector<vector<vector<int>>> generateChessboard(int boardSize, int squareWidth, int squareHeight) {
    vector<vector<int>> chessboard1;
    vector<vector<int>> chessboard2;

    for (int i = 0; i < boardSize; ++i) {
        vector<int> row;
        vector<int> row2;

        for (int j = 0; j < boardSize; ++j) {
            int squareValue = (i / squareHeight + j / squareWidth) % 2;
            int squareValue2 = ((i / squareHeight + j / squareWidth)+1) % 2;
            row.push_back(squareValue);
            row2.push_back(squareValue2);

        }

        chessboard1.push_back(row);
        chessboard2.push_back(row2);
    }

    return {chessboard1, chessboard2};
}

int countdif(const vector<vector<int>>& matrix1, const vector<vector<int>>& matrix2){
    int count = 0;
    const size_t numRows = matrix1.size();
    const size_t numCols = matrix1[0].size();

    #pragma omp parallel for reduction(+:count)
    for (size_t i = 0; i < numRows; ++i) {
        for (size_t j = 0; j < numCols; ++j) {
            if (matrix1[i][j] != matrix2[i][j]) {
                count++;
            }
        }
    }

    return count;
}

int main(){
    int n,k;
    cin >> n >>k;
    if (k == 0){
        cout << (int) n*n / 2;
    }
    else{
        vector<vector<int>> board(n, vector<int>(n, 0));
        vector<vector<int>> board2;
        for (int i = 0; i< k; i++){
            int x1,y1,x2,y2;
            cin >> x1 >> y1 >> x2 >> y2;
            for (int j = x1-1; j<=x2-1; j++){
                for (int b = y1-1; b <=y2-1; b++){
                    board[j][b] = 1;
                }
            }
        }
        int min1 = n*n;
        int nada = n/2;
        for (int h = 1; h <= nada; h++){
            if (n%h == 0){
                min1 = min(min1,min(countdif(board, generateChessboard(n, h,h)[0]), countdif(board, generateChessboard(n, h,h)[1])));
            }
            
        }
        cout << min1 << "\n";
        
        
    }

    return 0;
}

Compilation message (stderr)

chessboard.cpp:33: warning: ignoring '#pragma omp parallel' [-Wunknown-pragmas]
   33 |     #pragma omp parallel for reduction(+:count)
      |

• Subtask 1: 0 / 8
• Subtask 2: 0 / 8
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 0 / 23
• Subtask 6: 0 / 30