2788 Split Strings by Separator

This problem is just an implementation detail and does not require any algorithmic thinking whatsoever. But there’s a peculiarity in it regarding how regex works.

So, the separator that they provide is a special character and regex has special rules for special characters. If you want to match the special characters ($, %, ^, &, #, @, !, *, period), you have to prefix your regex string with \\Q and suffix it with \\E.

Code:

Java

class Solution {
    public List<String> splitWordsBySeparator(List<String> words, char separator) {
        List<String> res = new ArrayList<>();
 
        for (String w: words) {
            String[] splitWords = w.split("\\Q"+String.valueOf(separator)+"\\E");
 
            for (String sw: splitWords) {
                if (sw.length()>0) res.add(sw);
            }
 
        }
 
        return res;
    }
}

Big O Analysis

• Runtime The runtime complexity here is O(N*K), where K is length of the largest word in the array.
• Memory The memory usage is O(1) since we don’t use any extra datastructure.

— A

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