A valid IP address consists of exactly four integers separated by single dots. Each integer is between 0
and 255
(inclusive) and cannot have leading zeros.
- For example,
"0.1.2.201"
and"192.168.1.1"
are valid IP addresses, but"0.011.255.245"
,"192.168.1.312"
and"192.168@1.1"
are invalid IP addresses.
Given a string s
containing only digits, return all possible valid IP addresses that can be formed by inserting dots into s
. You are not allowed to reorder or remove any digits in s
. You may return the valid IP addresses in any order.
Example 1:
Input: s = "25525511135"
Output: ["255.255.11.135","255.255.111.35"]
Example 2:
Input: s = "0000"
Output: ["0.0.0.0"]
Example 3:
Input: s = "101023"
Output: ["1.0.10.23","1.0.102.3","10.1.0.23","10.10.2.3","101.0.2.3"]
Constraints:
-
1 <= s.length <= 20
-
s
consists of digits only.
SOLUTION:
class Solution:
def isValidChunk(self, s):
if len(s) > 1 and s[0] == "0":
return False
if int(s) < 0 or int(s) > 255:
return False
return True
def getAddress(self, s, curr, i, n):
op = []
if len(curr) == 4 and i == n:
return [curr]
for j in range(i + 1, n + 1):
chunk = s[i:j]
if self.isValidChunk(chunk):
val = self.getAddress(s, curr + [chunk], j, n)
op.extend(val)
return op
def restoreIpAddresses(self, s: str) -> List[str]:
val = self.getAddress(s, [], 0, len(s))
return [".".join(v) for v in val]
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