LeetCode 题解之Most Common Word

1、题目描述

2、题目分析

首先将输入句子拆分成单词，在这个过程中将所有大写字母变换成小写字母，将每一个单词作为一个字符串放入一个 map<string,int> 容器中，最后遍历容器，查找出现次数最多且没有在banned中出现的字符串。

3、代码

 1 string mostCommonWord(string paragraph, vector<string>& banned) {
 2         
 3         
 4         map<string,int> m;
 5         for( string::iterator it = paragraph.begin() ; it != paragraph.end(); ++it ){
 6             if( isalpha(*it) ){
 7                 *it = std::tolower(*it) ;
 8                 auto it_i = it ;
 9                 while( it_i != paragraph.end() && isalpha( *it_i ) ){
10                     *it_i = std::tolower( *it_i );
11                     ++it_i;
12                 }
13                 string s( it,it_i );
14                 m[s]++;
15                 it = (it_i == paragraph.end() )?it_i -1 : it_i ;
16             }
17         }
18         
19         int count = 0;
20         string result;
21         for( auto it_m = m.begin(); it_m != m.end(); ++it_m ){
22             if(   find( banned.begin(), banned.end(),it_m->first ) == banned.end() && it_m->second > count  ){
23                 result = it_m->first;
24                 count = it_m->second;
25             }
26         }
27         
28         return result ;
29         
30     }