Restore IP Addresses

Medium

https://leetcode.com/problems/restore-ip-addresses/

Given a string s containing only digits, return all possible valid IP addresses that can be obtained from s. You can return them in any order.

A valid IP address consists of exactly four integers, each integer is between 0 and 255, separated by single dots and cannot have leading zeros. For example, "0.1.2.201" and "192.168.1.1" are valid IP addresses and "0.011.255.245", "192.168.1.312" and "[email protected]" are invalid IP addresses.

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 = "1111"
Output: ["1.1.1.1"]

Example 4:

Input: s = "010010"
Output: ["0.10.0.10","0.100.1.0"]

Example 5:

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:

• 0 <= s.length <= 20
• s consists of digits only.