Problem C
Bendilfærslur
Languages
en
is
Níels is very forgetful and has a lot of domains. When he was setting up his website he forgot what domain the site had, but thankfully he had written down the IP address that the website was on. Now Níels needs to use the IP address to look up the domain so he can share the site with his friends. To do this he performs a reverse DNS lookup. But first he needs to convert his IP address to a PTR record (í. bendilfærslu), but he needs your help because he’s too busy centering the div on his website.
Input
The first line of the input contains a string. This string will be an IP address of either IPv4 or IPv6 form.
An IPv4 address consists of four parts. Each part is an integer from and including $0$ up to and including $255$ These parts are separated by a single period.
Some examples of valid IPv4 addresses are:
-
10.100.80.13
-
255.255.255.255
-
255.160.134.0
Some examples of invalid IPv4 addresses are:
-
300.1.35.28
-
255.255.255.254.1
-
127,0,0,1
An IPv6 address consists of eight parts. Each part is a four digit hexadecimal number. These hexadecimal numbers use the digits from $0$ to $9$ and the letters from $a$ to $f$. The eight parts are separated by single colons. In each part you may omit writing the leading zeros of the number. If two or more adjacent parts contain the number $0$ they may be omitted and in their place you write two colons. You are only allowed to do this in one place in the IP address.
Some examples of valid IPv6 addresses are:
-
ffff:dead:1337:beef:4321:f33d:2f92:3419
-
2001:db8:0:0:0:ff00:42:8329
-
::1
Some examples of invalid IPv6 addresses are:
-
0123:4567:89ab:cdef:ghij:klmn:opqr:stuv
-
ffff:1234::f6b90::abcd
-
2001:db8:0:0:0:ff00:42:8329:1234
Output
The output should contain, on a single line, the PTR record for the IP address.
The PTR record for an IPv4 address is such that the four parts have been reversed and in-addr.arpa. added to the end.
The PTR record for an IPv6 address is such that the colons are removed and a single period is placed between each symbol in the numbers, and that is then reversed. Then .ip6.arpa. is added to the end.
Scoring
|
Group |
Points |
Constraints |
|
1 |
30 |
The input consists solely of IPv4 addresses |
|
2 |
40 |
The input consists solely of IPv6 addresses where no zeros have been omitted |
|
3 |
30 |
No further constraints |
| Sample Input 1 | Sample Output 1 |
|---|---|
127.0.0.1 |
1.0.0.127.in-addr.arpa. |
| Sample Input 2 | Sample Output 2 |
|---|---|
2001:db8:0:0:0:ff00:42:8329 |
9.2.3.8.2.4.0.0.0.0.f.f.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa. |
| Sample Input 3 | Sample Output 3 |
|---|---|
::1 |
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. |
