determinant-of-a-matrix.java

class Solution
{
    static int determinantOfMatrix(int matrix[][], int n)
    {
        if (n == 1) {
            return matrix[0][0];
        }
        int det = 0;
        int sign = 1;
        for (int i = 0; i < n; i++)
        {
            int[][] submatrix = new int[n - 1][n - 1];
            getCofactor(matrix, submatrix, 0, i, n);
            det += sign * matrix[0][i] * determinantOfMatrix(submatrix, n - 1);
            sign = -sign;
        }
        return det;
    }
    static void getCofactor(int matrix[][], int temp[][], int p, int q, int n)
    {
        int i = 0, j = 0;
        for (int row = 0; row < n; row++)
        {
            for (int col = 0; col < n; col++)
            {
                if (row != p && col != q)
                {
                    temp[i][j++] = matrix[row][col];

                    if (j == n - 1)
                    {
                        j = 0;
                        i++;
                    }
                }
            }
        }
    }
}