11errores

public class Sudoku {
    static void solveSudoku(int[][] sudoku){
        int row, column;

        // If there is no unassigned location, we are done
        if (FreeLocation(sudoku, row, column))
            return true;
         for (int number = 1; number <= sudoku.length; number++)
        {
            if (CheckIfRepeated(sudoku, row, column, number))
            {
                sudoku[row][column] = number;

                if (solveSudoku(sudoku))
                    return true;

            /*backtrack*/
            sudoku[row][column] = 0;
            }
        }
    return false;
    }

private static bool FreeLocation(int[][] sudoku) {
    for (int row = 0; row < sudoku.length; row++) // 9
        for (int column = 0; column < sudoku.length; column++) // 9
            if (sudoku[row][column] == 0)
                return true;
    return false;
}



/* for the next 3 functions, "false" means that the value was found, and "true" means the opposite.
I did it so for a better use of the "if" statement: if the three are true,
then it's safe to use the value of "number" in CheckIfRepeated*/

private static bool IsNumberRepeatedInRow(int[][] sudoku, int row, int column, int number) {
    for (column = 0; column < sudoku.length ; column++)
                if (sudoku[row][column] == number)
                    return false;
                return true;
}

private static bool IsNumberRepeatedInColumn(int[][] sudoku, int row, int column, int number) {
    for (row = 0; row < sudoku.length ; row++)
            if (sudoku[row][column] == number)
                return false;
            return true;
}

private static bool IsNumberRepeatedInSquare(int[][] sudoku, int row, int column, int number){
    for (int rowh = row - row%3 ; rowh < row+3 ; rowh++) {
            for(int colh = column - column%3 ; colh < column+3 ; colh++) {
                if (sudoku[rowh][colh] == number)
                    return false;
                return true;
            }
    }
}

private static bool CheckIfRepeated(int[][] sudoku, int row, int column, int number) {
    if (IsNumberRepeatedInRow(sudoku, row, column, number) &&
        IsNumberRepeatedInColumn(sudoku, row, column, number) &&
        IsNumberRepeatedInSquare(sudoku, row, column, number));
        return true;
    return false;
}

}