Reorder Log Files

String

Easy

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

For each log, the first word in each log is an alphanumericidentifier. 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 logsletter-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"]

Note:

1. 0 <= logs.length <= 100
2. 3 <= logs[i].length <= 100
3. logs[i]is guaranteed to have an identifier, and a word after the identifier.

Analysis

Write a custom sort (compare function)

class Solution {
public String[] reorderLogFiles(String[] logs) {
Comparator<String> cmp = new Comparator<String>() {

@Override
public int compare(String log1, String log2) {
int i1 = log1.indexOf(" ");
int i2 = log2.indexOf(" ");

char ch1 = log1.charAt(i1 + 1);
char ch2 = log2.charAt(i2 + 1);

if (Character.isDigit(ch1)) {
if (Character.isDigit(ch2)) {
return 0;
} else {
return 1;
}
}
if (Character.isDigit(ch2)) {
return -1;
}
int comp = log1.substring(i1 + 1).compareTo(log2.substring(i2 + 1));
if (comp == 0) {
return log1.substring(0, i1).compareTo(log2.substring(0, i2));
}
return comp;
}
};
Arrays.sort(logs, cmp);
return logs;
}
}

https://leetcode.com/problems/reorder-log-files/