大厂Java笔试题之计算日期是一年中第几天

本文主要是介绍大厂Java笔试题之计算日期是一年中第几天，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

题目：描述根据输入的日期，计算是这一年的第几天。保证年份为4位数且日期合法。进阶：时间复杂度：O(n) ，空间复杂度：O(1) 输入描述：输入一行，每行空格分割，分别是年，月，日输出描述：输出是这一年的第几天

示例输入：2012 12 31 输出：366

public class Demo14 {public static void main(String[] args) {Scanner in = new Scanner(System.in);// 注意 hasNext 和 hasNextLine 的区别while (in.hasNextLine()) { // 注意 while 处理多个 caseString s = in.nextLine();String[] split = s.split(" ");int year = Integer.parseInt(split[0]);int month = Integer.parseInt(split[1]);int day = Integer.parseInt(split[2]);System.out.println(calculateDayOfYear(year, month, day));}}private static boolean isValidDate(int year, int month, int day) {if (year < 1000 || year > 9999) {return false;}if (month < 1 || month > 12) {return false;}int[] daysInMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};if (isLeapYear(year)) {daysInMonth[1]++; // February has 29 days in a leap year}return day >= 1 && day <= daysInMonth[month - 1];}private static boolean isLeapYear(int year) {return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);}private static int calculateDayOfYear(int year, int month, int day) {if (!isValidDate(year, month, day)) {return 0;}int[] daysInMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};int sum = 0;for (int i = 0; i < month - 1; i++) {sum += daysInMonth[i];}if (isLeapYear(year) && month > 2) {sum++; // Add an extra day for February in a leap year}return sum + day;}
}

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