Baffling Birthdays

Challenge Overview

Estimate the birthday paradox's probabilities.

Visit the baffling-birthdays exercise on Exercism to read the full instructions and download the exercise files.

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The following are the top 3 community solutions by stars:

Solution 1 by @menketechnologies (⭐ 0) — View on Exercism
Solution 2 by @KarinB (⭐ 0) — View on Exercism
Solution 3 by @NamuChon (⭐ 0) — View on Exercism

Source: Exercism java/baffling-birthdays

💡 View Solution

public class BafflingBirthdays {
    private static final long MIN_DAY = LocalDate.of(1970, 1, 1).toEpochDay();
    private static final long MAX_DAY = LocalDate.of(9999, 12, 31).toEpochDay();

    public boolean sharedBirthday(List<LocalDate> birthDates) {
        return birthDates.stream()
                .map(date -> date.withYear(9999))
                .distinct()
                .count() != birthDates.size();
    }