Difference Between Ones and Zeros in Row and Column

You are given a 0-indexed m x n binary matrix grid.

A 0-indexed m x n difference matrix diff is created with the following procedure:

• Let the number of ones in the i<sup>th</sup> row be onesRow<sub>i</sub>.

• Let the number of ones in the j<sup>th</sup> column be onesCol<sub>j</sub>.

• Let the number of zeros in the i<sup>th</sup> row be zerosRow<sub>i</sub>.

• Let the number of zeros in the j<sup>th</sup> column be zerosCol<sub>j</sub>.

• diff[i][j] = onesRow<sub>i</sub> + onesCol<sub>j</sub> - zerosRow<sub>i</sub> - zerosCol<sub>j</sub>

Return the difference matrix diff.

LeetCode Problem - 2482

class Solution {
    public int[][] onesMinusZeros(int[][] grid) {
        int rows = grid.length;           // Number of rows in the grid
        int cols = grid[0].length;        // Number of columns in the grid
        int[][] diff = new int[rows][cols]; // Resulting difference grid

        int[] rowDiff = new int[rows];    // Array to store the count of 1s in each row
        int[] colDiff = new int[cols];    // Array to store the count of 1s in each column

        // First pass: Count the number of 1s in each row and each column
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                if (grid[i][j] == 1) {
                    rowDiff[i]++;   // Increment the count of 1s in row i
                    colDiff[j]++;   // Increment the count of 1s in column j
                }
            }
        }

        // Second pass: Calculate the result for each cell in the diff array
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                // Calculate the number of 1s and 0s in the row and column of the current cell
                int onesRowi = rowDiff[i];                // Number of 1s in the current row
                int onesColj = colDiff[j];                // Number of 1s in the current column
                int zerosRowi = cols - rowDiff[i];        // Number of 0s in the current row
                int zerosColj = rows - colDiff[j];        // Number of 0s in the current column

                // Calculate the difference as the number of 1s in the row and column minus the number of 0s
                diff[i][j] = onesRowi + onesColj - zerosRowi - zerosColj;
            }
        }

        // Return the resulting grid with differences
        return diff;
    }
}