统计共同度过的日子数

/*
题目思路：
1. 使用Java Stream API转换日期并计算重叠天数。
2. 首先将日期字符串转换为年内的第几天。
3. 使用Stream计算重叠天数。
*/

import java.util.Arrays;

public class SolutionStream {
    private static final int[] DAYS_IN_MONTH = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    // 将日期转换为年内的第几天
    private int convertToDayOfYear(String date) {
        String[] parts = date.split("-");
        int month = Integer.parseInt(parts[0]);
        int day = Integer.parseInt(parts[1]);
        return Arrays.stream(DAYS_IN_MONTH, 0, month - 1).sum() + day;
    }

    public int countDaysTogether(String arriveAlice, String leaveAlice, String arriveBob, String leaveBob) {
        int arriveAliceDay = convertToDayOfYear(arriveAlice);
        int leaveAliceDay = convertToDayOfYear(leaveAlice);
        int arriveBobDay = convertToDayOfYear(arriveBob);
        int leaveBobDay = convertToDayOfYear(leaveBob);

        // 计算重叠的开始和结束日期
        int startOverlap = Math.max(arriveAliceDay, arriveBobDay);
        int endOverlap = Math.min(leaveAliceDay, leaveBobDay);

        // 计算重叠天数
        return Math.max(0, endOverlap - startOverlap + 1);
    }
}