Problem: Reorder Log Files

Question

You have an array of logs. Each log is a space delimited string of words.

For each log, the first word in each log is an alphanumeric identifier. Then, either:

Each word after the identifier will consist only of lowercase letters, or;
Each word after the identifier will consist only of digits.
We will call these two varieties of logs letter-logs and digit-logs. It is guaranteed that each log has at least one word after its identifier.

Reorder the logs so that all of the letter-logs come before any digit-log. The letter-logs are ordered lexicographically ignoring identifier, with the identifier used in case of ties. The digit-logs should be put in their original order.

Return the final order of the logs.

Example 1:

Input: ["a1 9 2 3 1","g1 act car","zo4 4 7","ab1 off key dog","a8 act zoo"]
Output: ["g1 act car","a8 act zoo","ab1 off key dog","a1 9 2 3 1","zo4 4 7"]

Solution

TODO

Code

class Solution {
    public String[] reorderLogFiles(String[] logs) {
        Comparator<String> myComp = new Comparator<String>() {
            @Override
            public int compare(String s1, String s2) {
                int s1si = s1.indexOf(' ');
                int s2si = s2.indexOf(' ');
                char s1fc = s1.charAt(s1si+1);
                char s2fc = s2.charAt(s2si+1);
                if(s1fc <= '9' && s2fc <= '9') return 0;
                if(s1fc <= '9' && s2fc > '9') return 1;
                if(s1fc > '9' && s2fc <= '9') return -1;

                int preCompute = s1.substring(s1si+1).compareTo(s2.substring(s2si+1));
                if (preCompute == 0) return s1.substring(0,s1si).compareTo(s2.substring(0,s2si));
                return preCompute;
            }
        };

        Arrays.sort(logs, myComp);
        return logs;
    }
}

Performance