[Hackerrank] Time Conversion

Problem

Given a time in AM/PM format, convert it to military (24-hour) time.

Note: Midnight is 12:00:00AM on a 12-hour clock and 00:00:00 on a 24-hour clock. Noon is 12:00:00PM on a 12-hour clock and 12:00:00 on a 24-hour clock.

Input Format

A time in 12-hour clock format (i.e.: hh:mm:ssAM or hh:mm:ssPM), where 01≤hh≤12.

Output Format

Convert and print the given time in 24-hour format, where 00≤hh≤23.

Sample Input

07:05:45PM

Sample Output

19:05:45

Explanation

7 PM is after noon, so you need to add 12 hours to it during conversion. 12 + 7 = 19. Minutes and seconds do not change in 12-24 hour time conversions, so the answer is 19:05:45.

Analysis

• 首先截取后两位字母，判断是AM还是PM
• 注意关于时间，只需要改hour
• 取hour
• 如果PM
• 若hour<12, 则加12，否则不变
• 如 12:xx:xxPM, should be 12:xx:xx
• 11:xx:xxPM should be 23:xx:xx
• 如果AM
• 若hour>12, 则转为0
• 否则不变

Code