468. Validate IP Address

• 468. Validate IP Address
  • Description
  • Intuition
  • Pitfall
    • JDK Split API
    • IPv4
    • IPv6
  • Solution

Description

Here

Intuition

Pitfall

这题目坑比较多……

JDK Split API

There are 2 pitfalls for split API).

1. The parameter is regular expression. Therefore, . needs excape.
2. The last empty string will be ignored.
   1. For example, "abc.edf.".split("\\.") will be split to ["abc", "edf"]

IPv4

The IPv 4 section has the following rules:

1. The IP ranges from [0, 255]
2. The IP cannot startswith 0
   1. For example, 01 or 023 is invalid
3. The IP cannot empty
   1. 1..1.1 is invalid
4. 这边最好直接先检查section的长度，验证数字还可以stirng很长，1111111...111，然后overflow，回到[0, 255]

IPv6

The IPv6 section should be following rules:

1. 8 sections seperated by :
2. Every section's length ranges from [1, 4]
3. It can contain leading zeros
4. Every char should be a Hex char

Solution