937. Reorder Data in Log Files

Tags: ‘String’ ‘Sort’

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: logs = ["dig1 8 1 5 1","let1 art can","dig2 3 6","let2 own kit dig","let3 art zero"]
Output: ["let1 art can","let3 art zero","let2 own kit dig","dig1 8 1 5 1","dig2 3 6"]

Constraints:

0 <= logs.length <= 100
3 <= logs[i].length <= 100
logs[i] is guaranteed to have an identifier, and a word after the identifier.

Solution

Use Lambda function

public String[] reorderLogFiles(String[] logs) {
    Arrays.sort(logs, (s1, s2) -> {
        String[] split1 = s1.split(" ", 2);
        String[] split2 = s2.split(" ", 2);

        boolean isDigit1 = Character.isDigit(split1[1].charAt(0));
        boolean isDigit2 = Character.isDigit(split2[1].charAt(0));

        if(!isDigit1 && !isDigit2) {
            // both letter-logs. 
            int comp = split1[1].compareTo(split2[1]);
            if (comp == 0) return split1[0].compareTo(split2[0]);
            else return comp;
        } else if (isDigit1 && isDigit2) {
            // both digit-logs. So keep them in original order
            return 0; 
        } else if (isDigit1 && !isDigit2) {
            // first is digit, second is letter. bring letter to forward.
            return 1;
        } else {
            //first is letter, second is digit. keep them in this order.
            return -1; 
        }
    });
    return logs;
}

public String[] reorderLogFiles(String[] logs) {
    Comparator<String> myComp = new Comparator<String>(){
        @Override
        public int compare(String s1, String s2) {
            String[] split1 = s1.split(" ", 2);
            String[] split2 = s2.split(" ", 2);
            
            boolean isDigit1 = Character.isDigit(split1[1].charAt(0));
            boolean isDigit2 = Character.isDigit(split2[1].charAt(0));
            
            if (!isDigit1 && !isDigit2) {
                int comp = split1[1].compareTo(split2[1]);
                if (comp == 0) {
                    comp = split1[0].compareTo(split2[0]);
                }
                return comp;
            } else if (isDigit1 && isDigit2) {
                return 0; // both are digits, keep original order
            } else if (isDigit1) {
                return 1; // s1 is digit, put behand
            } else {
                return -1;
            }
        }
    };
    
    Arrays.sort(logs, myComp);
    return logs;
}

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937. Reorder Data in Log Files