Problem D
Best Before
Given a possibly ambiguous date “$A/B/C$”, where $A, B, C$ are integers between $0$ and $2999$, output the earliest possible legal date between Jan 1, 2000 and Dec 31, 2999 (inclusive) using them as day, month and year (but not necessarily in that order).
Recall that a year is a leap year (has 366 days) if the year is divisible by 4, unless it is divisible also by 100 but not by 400 (so 2000 is a leap year, 2100 is not a leap year, and 2012 is a leap year).
Input
The input file consists of a single line containing three integers separated by “/”. There are no extra spaces around the “/”. Years may be truncated to two digits and may in that case also omit the leading $0$ (if there is one), so $2000$ could be given as “2000”, “00” or “0” (but not as an empty string). Months and days may be zero-padded. You may assume that the year, when given with four digits, is between $2000$ and $2999$. At most one of the integers has four digits, and the others have one or two digits.
Output
Output a single line giving the earliest legal date possible given the above constraints. The output should be formatted as year-month-day, where year has four digits, and month and day have two digits each (zero padding), for example “2011-07-15”.
If there is no legal date (subject to the above constraints) then output a single line with the original string followed by the words “is illegal”.
| Sample Input 1 | Sample Output 1 |
|---|---|
02/4/67 |
2067-02-04 |
| Sample Input 2 | Sample Output 2 |
|---|---|
31/9/73 |
31/9/73 is illegal |
