Suppose there are n student records, and each record includes three keywords: name, gender and date of birth (such as 199506 or 200112year and month only). Please design an efficient algorithm to make all records in ascending order according to the date of birth. If the date of birth is the same, it will be ordered by gender (girls first, boys last). Please write down the idea and steps of the algorithm, and analyze the time complexity of the algorithm.