Validate IP Address — LeetCode 468 Python Solution
MediumString
- Problem
- #468
- Pattern
- Hash Map
- Reading time
- 5 min
- Source
- leetcode.com
The problem
Given a string queryIP, return "IPv4" if IP is a valid IPv4 address, "IPv6" if IP is a valid IPv6 address or "Neither" if IP is not a correct IP of any type. A valid IPv4 address is an IP in the form "x1.x2.x3.x4" where 0 <= xi <= 255 and xi cannot contain leading zeros.
Example
- Input
- queryIP = "172.16.254.1"
- Output
- "IPv4"
- Explanation
- This is a valid IPv4 address, return "IPv4".
Python solution
Python
class Solution:
def validIPAddress(self, queryIP: str) -> str:
def is_ipv4(s: str) -> bool:
ss = s.split(".")
if len(ss) != 4:
return False
for t in ss:
if len(t) > 1 and t[0] == "0":
return False
if not t.isdigit() or not 0 <= int(t) <= 255:
return False
return True
def is_ipv6(s: str) -> bool:
ss = s.split(":")
if len(ss) != 8:
return False
for t in ss:
if not 1 <= len(t) <= 4:
return False
if not all(c in "0123456789abcdefABCDEF" for c in t):
return False
return True
if is_ipv4(queryIP):
return "IPv4"
if is_ipv6(queryIP):
return "IPv6"
return "Neither"Complexity
| Measure | Complexity |
|---|---|
| Time | O(n) |
| Space | O(n) auxiliary |
Pattern: Hash Map
Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 468. Validate IP Address is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.
The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 468. Validate IP Address?
- LeetCode 468. Validate IP Address is rated Medium on LeetCode.
- What is the time complexity of LeetCode 468. Validate IP Address?
- The Python solution on this page runs in O(n).
- What is the space complexity of LeetCode 468. Validate IP Address?
- The Python solution on this page uses O(n) auxiliary space.
- What topics does LeetCode 468. Validate IP Address cover?
- LeetCode 468. Validate IP Address is tagged String on LeetCode.