【leetcode刷题】T93-最常见的单词

示例：

输入: 
paragraph = "Bob hit a ball, the hit BALL flew far after it was hit."
banned = ["hit"]
输出: "ball"
解释: 
"hit" 出现了次，但它是一个禁用的单词。
"ball" 出现了次，是段落里出现次数最多的，且不在禁用列表中的单词。 
注意，所有这些单词在段落里不区分大小写，标点符号需要忽略（即使是紧挨着单词也忽略， 比如 "ball,"）， 
"hit"不是最终的答案，虽然它出现次数更多，但它在禁用单词列表中。

class Solution(object):
    def mostCommonWord(self, paragraph, banned):
        """
        :type paragraph: str
        :type banned: List[str]
        :rtype: str
        """
        
        # 得到每个单词计数
        words = []
        start = 
        for i in range(len(paragraph)):
            num = ord(paragraph[i])
            if  <= num <= + or  <= num <= +:
                continue
            else:
                if i - start > :
                    words.append(paragraph[start: i].lower())
                start = i+
        if len(paragraph) - start > :
            words.append(paragraph[start:].lower())
        
        count = {}
        for w in words:
            count[w] = count.get(w, ) + 

        # 按照计数大小排序
        count_ls = list(count.items())
        count_ls = sorted(count_ls, key=lambda x: x[], reverse=True)
        
        # 得到非禁词的最大计数词(按照题意，保证有)
        banned_st = set(banned)
        for ci in count_ls:
            if ci[] not in banned:
                return ci[]

class Solution {
public:
    string mostCommonWord(string paragraph, vector<string>& banned) {
        
        // 转换为单词
        vector<string> words;
        string tmp;
        for(int i=; i<paragraph.size(); i++){
            if(paragraph[i] >=  && paragraph[i] <= +)
                tmp += (paragraph[i] + );
            else{
                if(paragraph[i] >=  && paragraph[i] <= +)
                    tmp += paragraph[i];
                else{
                    if(tmp != "")
                        words.push_back(tmp);
                    tmp = "";
                }
            }
        }
        if(tmp != "")
            words.push_back(tmp);
        
        // 单词计数
        map<string, int> d;
        for(auto w: words){
            d[w]++;
        }
        
        // 取得最大值
        set<string> banned_set(banned.begin(), banned.end());
        string res = "";
        for(map<string, int>::iterator it = d.begin(); it != d.end(); it++){
            if((res == "" || it->second > d[res]) && banned_set.find(it->first) == banned_set.end())
                res = it->first;
        }
        return res;
    }
};