leetecode937 - Reorder Data in Log Files - easy

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:

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.

 

stable sort练一下custom comparator

comparison function object (i.e. an object that satisfies the requirements of Compare) which returns ​true if the first argument is less than (i.e. is ordered before) the second.

The signature of the comparison function should be equivalent to the following:

 bool cmp(const Type1 &a, const Type2 &b);

 

1. 数字的只跟字母的比，本身不互相比较了，所以a是数字组的话return false，b是数字组的话return true，目的都是让它们去后面

2. 字母间比较，除去identifier无大小之分的话，比包含identifier

 

string之间比较用compare!!一样的话s1.compare(s2) == 0

 

实现：

class Solution {
private:
    static bool cmp(string a, string b){
        string afterIdA = a.substr(a.find(' ')+1);
        string afterIdB = b.substr(b.find(' ')+1);
        
        if (isdigit(afterIdA[0]))
            return false;
        else if (isdigit(afterIdB[0]))
            return true;
        
        if (afterIdA.compare(afterIdB) != 0)
            return afterIdA.compare(afterIdB) < 0;
        else
            return a.compare(b);
    }
public:
    vector<string> reorderLogFiles(vector<string>& logs) {
        stable_sort(logs.begin(), logs.end(), cmp);
        return logs;
    }
};