Reformat_Date.md

Reformat Date

Alias

• Leetcode (1507): Reformat Date

Problem

Given a date string in the form Day Month Year, where:

• Day is in the set {"1st", "2nd", "3rd", "4th", ..., "30th", "31st"}.
• Month is in the set {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}.
• Year is in the range [1900, 2100].

Convert the date string to the format YYYY-MM-DD, where:

• YYYY denotes the 4 digit year.
• MM denotes the 2 digit month.
• DD denotes the 2 digit day.

Examples

• Example 1
  • Input

    "20th Oct 2052"
    

  • Output

    "2052-10-20"
    

• Example 2
  • Input

    "6th Jun 1933"
    

  • Output

    "1933-06-06"
    

• Example 3
  • Input

    "26th May 1960"
    

  • Output

    "1960-05-26"
    

Solutions

• Solution 1

  class Solution {
      public String reformatDate(String date) {
          Map<String,String> m = new HashMap<>();
          m.put("Jan","01"); m.put("Feb","02"); m.put("Mar","03"); m.put("Apr","04");
          m.put("May","05"); m.put("Jun","06"); m.put("Jul","07"); m.put("Aug","08");
          m.put("Sep","09"); m.put("Oct","10"); m.put("Nov","11"); m.put("Dec","12");
  
          StringBuilder sb = new StringBuilder();
          if(date.length()==13){
              return sb.append(date.substring(9))
              .append("-")
              .append(m.get(date.substring(5,8)))
              .append("-").append(date.substring(0,2))
              .toString();
          }
          return sb.append(date.substring(8))
          .append("-")
          .append(m.get(date.substring(4,7)))
          .append("-0")
          .append(date.substring(0,1))
          .toString();
      }
  }