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

string mostCommonWord(string paragraph, vector<string>& banned) {
        
        
        map<string,int> m;
        for( string::iterator it = paragraph.begin() ; it != paragraph.end(); ++it ){
            if( isalpha(*it) ){
                *it = std::tolower(*it) ;
                auto it_i = it ;
                while( it_i != paragraph.end() && isalpha( *it_i ) ){
                    *it_i = std::tolower( *it_i );
                    ++it_i;
                }
                string s( it,it_i );
                m[s]++;
                it = (it_i == paragraph.end() )?it_i -1 : it_i ;
            }
        }
        
        int count = 0;
        string result;
        for( auto it_m = m.begin(); it_m != m.end(); ++it_m ){
            if(   find( banned.begin(), banned.end(),it_m->first ) == banned.end() && it_m->second > count  ){
                result = it_m->first;
                count = it_m->second;
            }
        }
        
        return result ;
        
    }