# LeetCode 1507. Reformat Date

## Description

https://leetcode.com/problems/reformat-date/

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.

Example 1:

```Input: date = "20th Oct 2052"
Output: "2052-10-20"
```

Example 2:

```Input: date = "6th Jun 1933"
Output: "1933-06-06"
```

Example 3:

```Input: date = "26th May 1960"
Output: "1960-05-26"
```

Constraints:

• The given dates are guaranteed to be valid, so no error handling is necessary.

## Explanation

Do the format conversion base on the problem description.

## Python Solution

``````class Solution:
def reformatDate(self, date: str) -> str:
mapping = {"Jan": "01", "Feb": "02", "Mar": "03", "Apr": "04", "May": "05", "Jun": "06", "Jul": "07", "Aug": "08", "Sep": "09", "Oct": "10", "Nov": "11", "Dec": "12"}

year = date.split()[2]
month = date.split()[1]
day = date.split()[0]
formatted_day = ""

for c in day:
if not c.isdigit():
break
else:
formatted_day += c

if len(formatted_day) == 1:
formatted_day = "0" + formatted_day

reformatted_date = year + "-" + mapping[month] + "-" + formatted_day

return reformatted_date``````
• Time Complexity: O(N).
• Space Complexity: O(N).