LeetCode 1108. Defanging an IP Address

原题链接在这里：https://leetcode.com/problems/defanging-an-ip-address/

题目：

Given a valid (IPv4) IP address, return a defanged version of that IP address.

A defanged IP address replaces every period "." with "[.]".

Example 1:

Input: address = "1.1.1.1"
Output: "1[.]1[.]1[.]1"

Example 2:

Input: address = "255.100.50.0"
Output: "255[.]100[.]50[.]0"

Constraints:

• The given address is a valid IPv4 address.

题解：

Replace all "." with "[.]".

Time Complexity: O(n). n = address.length().

Space: O(n).

AC Java:

class Solution {
    public String defangIPaddr(String address) {
        if(address == null || address.length() == 0){
             return address;
        }
        
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i<address.length(); i++){
            char c = address.charAt(i);
            if(c == '.'){
                sb.append("[.]");
            }else{
                sb.append(c);
            }
        }
        
        return sb.toString();
    }
}