The Time Conversion – Java HackerRank Solution

Objective:

The goal of this ‘time conversion‘ problem is to convert a given time in a 12-hour AM/PM format to a 24-hour military time format. You are given a time in 12-hour AM/PM format, and you need to convert it to 24-hour military time format.

Input Format:

• In this time conversion problem a single string s representing the time in a 12-hour clock format (i.e., hh:mm:ssAM or hh:mm:ssPM), where:
  • hh is the hour (01 to 12)
  • mm is the minutes (00 to 59)
  • ss is the seconds (00 to 59)
  • The last two characters indicate AM or PM

Output Format:

• In time conversion a single string representing the time in 24-hour military format (i.e., HH:MM:SS), where:
  • HH is the hour (00 to 23)
  • MM is the minutes (00 to 59)
  • SS is the seconds (00 to 59)

Example:

1. If the input string is 07:05:45PM, the output should be 19:05:45.
2. If the input string is 12:40:22AM, the output should be 00:40:22.

Steps to Solve Time Conversion:

1. Extract the Parts: Separate the hours, minutes, seconds, and period (AM/PM) from the input string.
2. Convert Hour:
   • If the period is AM:
     • If the hour is 12, set the hour to 00.
     • Otherwise, keep the hour unchanged (convert to two-digit format if necessary).
   • If the period is PM:
     • If the hour is 12, keep the hour unchanged.
     • Otherwise, add 12 to the hour (to convert it to 24-hour format).
3. Reconstruct the Time: Combine the converted hour, minutes, and seconds into the final 24-hour format string.

Edge Cases to Consider:

• 12:00:00AM should convert to 00:00:00.
• 12:00:00PM should convert to 12:00:00.

Time Conversion HackerRank Problem Snippet:

Time Conversion 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 'timeConversion' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts STRING s as parameter.
     */

    public static String timeConversion(String s) {
    // Write your code here
        String response = "";
        String[] store = s.substring(0, 8).split(":");
        String hour = store[0];
        if (s.contains("AM")) {
            response = (store[0].equals("12") ? "00" : hour) + ":" + store[1] + ":" + store[2];
        } else {
            int hour2 = Integer.parseInt(hour);
            if (hour2 < 12)
                hour2 += 12;
            response = hour2 + ":" + store[1] + ":" + store[2];
        }
        return respons;
    }

}

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 s = bufferedReader.readLine();

        String result = Result.timeConversion(s);

        bufferedWriter.write(result);
        bufferedWriter.newLine();

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

You also may like this,

All HackerRank Solutions in Java
Java Interview Preparation