[Java] HackerRank_Java Static Initializer Block과 Date and Time

[Problem]

Static initialization blocks are executed when the class is loaded, and you can initialize static variables in those blocks.

It's time to test your knowledge of Static initialization blocks. You can read about it here.

You are given a class Solution with a main method. Complete the given code so that it outputs the area of a parallelogram with breadth B and height H. You should read the variables from the standard input.

If B ≤ 0 or H ≤ 0, the output should be "java.lang.Exception: Breadth and height must be positive" without quotes.

Input Format

There are two lines of input. The first line contains B: the breadth of the parallelogram. The next line contains H: the height of the parallelogram.

Constraints

• -100 ≤ B ≤100
• -100 ≤ H ≤100

Output Format

If both values are greater than zero, then the main method must output the area of the parallelogram. Otherwise, print "java.lang.Exception: Breadth and height must be positive" without quotes.

Sample input 1

1

3

Sample output 1

3

Sample input 2

-1

2

Sample output 2

java.lang.Exception: Breadth and height must be positive

[Solution]

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    public static int B;
    public static int H;
    private static boolean flag;
    static {
        Scanner scan = new Scanner(System.in);
        B = scan.nextInt();
        H = scan.nextInt();
        if ( B <= 0 || H <= 0 ) {
            System.out.println("java.lang.Exception: Breadth and height must be positive");
            flag = false;
        } else {
            flag = true;    
        }
        
    }
    
public static void main(String[] args){
		if(flag){
			int area=B*H;
			System.out.print(area);
		}
		
	}//end of main

}//end of class

[Problem]

The Calendar class is an abstract class that provides methods for converting between a specific instant in time and a set of calendar fields such as YEAR, MONTH, DAY_OF_MONTH, HOUR, and so on, and for manipulating the calendar fields, such as getting the date of the next week.

---

You are given a date. You just need to write the method, getDay, which returns the day on that date. To simplify your task, we have provided a portion of the code in the editor.

For example, if you are given the date August 14th 2017, the method should return MONDAY as the day on that date.

Input Format

A single line of input containing the space separated month, day and year, respectively, in MM DD YYYY format.

Constraints

• 2000 ≤ year ≤3000

Output Format

Output the correct day in capital letters.

Sample Input

08 05 2015

Sample Output

WEDNESDAY

Explanation

The day on August 5th 2015 was WEDNESDAY.

[Solution]

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'findDay' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts following parameters:
     *  1. INTEGER month
     *  2. INTEGER day
     *  3. INTEGER year
     */

    public static String findDay(int month, int day, int year) {
        String[] dayOfWeek = { "SUNDAY", "MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY", "SATURDAY"};
        Calendar cal = Calendar.getInstance();
        cal.set(year, month - 1, day);
        
        return dayOfWeek[cal.get(Calendar.DAY_OF_WEEK) - 1];
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        int month = Integer.parseInt(firstMultipleInput[0]);

        int day = Integer.parseInt(firstMultipleInput[1]);

        int year = Integer.parseInt(firstMultipleInput[2]);

        String res = Result.findDay(month, day, year);

        bufferedWriter.write(res);
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}