https://leetcode.com/problems/reorder-log-files/
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"]
Approach 1: Custom Sort
Instead of sorting in the default order, we'll sort in a custom order we specify.
The rules are:
- Letter-logs come before digit-logs;
- Letter-logs are sorted alphanumerically, by content then identifier;
- Digit-logs remain in the same order.
It is straightforward to translate these ideas into code.
public String[] reorderLogFiles(String[] logs) {
Arrays.sort(logs, (log1, log2) -> {
String[] split1 = log1.split(" ", 2);
String[] split2 = log2.split(" ", 2);
boolean isDigit1 = Character.isDigit(split1[1].charAt(0));
boolean isDigit2 = Character.isDigit(split2[1].charAt(0));
if (!isDigit1 && !isDigit2) {
int cmp = split1[1].compareTo(split2[1]);
if (cmp != 0)
return cmp;
return split1[0].compareTo(split2[0]);
}
return isDigit1 ? (isDigit2 ? 0 : 1) : -1;
});
return logs;
}
