LeetCode 937. Reorder Data in Log Files

题目标签：String

　　写一个comparator，先分离identifier 和 content，然后分情况比较：

　　　　1. 两个 log 都是 letter logs，先比较 content，如果一样content 再比较 identifiers

　　　　2. 一个letter log， 一个 digit log

　　　　3. 两个都是 digit logs

　　具体看code。

Java Solution: 

Runtime:  14ms, faster than 12.57% 

Memory Usage: 46.5MB, less than 5.13%

完成日期：01/26/2021

关键点：override compare

class Solution {
    public String[] reorderLogFiles(String[] logs) {

        Comparator<String> myComp = new Comparator<String>() {
            @Override
            public int compare(String log1, String log2) {
                // split each log into two parts: <identifier, content>
                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));

                // case 1). both logs are letter-logs
                if (!isDigit1 && !isDigit2) {
                    // first compare the content
                    int cmp = split1[1].compareTo(split2[1]);
                    if (cmp != 0)
                        return cmp;
                    // logs of same content, compare the identifiers
                    return split1[0].compareTo(split2[0]);
                }

                // case 2). one of logs is digit-log
                if (!isDigit1 && isDigit2)
                    // the letter-log comes before digit-logs
                    return -1;
                else if (isDigit1 && !isDigit2)
                    return 1;
                else
                    // case 3). both logs are digit-log
                    return 0;
            }
        };

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

参考资料：https://leetcode.com/problems/reorder-data-in-log-files/solution/

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