leetcode.30. Substring with Concatenation of All Words

You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) ins that is a concatenation of each word in words exactly once and without any intervening characters.

For example, given:
s: "barfoothefoobarman"
words: ["foo", "bar"]

You should return the indices: [0,9].
(order does not matter).

class Solution {public:    vector<int> findSubstring(string s, vector<string>& words) {        if (words.empty())            return vector<int>();        vector<int> ret;        //记录所给words中每个单词的出现次数        map<string, int> word_count;        //每个单词的长度相同        int word_size = strlen(words[0].c_str());        int word_nums = words.size();        //所给匹配字符串的长度        int s_len = strlen(s.c_str());        for (int i = 0; i < word_nums; i++)            ++word_count[words[i]];        int i, j;        map<string, int> temp_count;        for (i = 0; i < s_len - word_nums*word_size + 1; ++i)        {            temp_count.clear();            for (j = 0; j < word_nums; j++)            {                //检验当前单词是否属于words以及出现的次数是否一致                string word = s.substr(i + j*word_size, word_size);                if (word_count.find(word) != word_count.end())                {                    ++temp_count[word];                    //如果出现的次数与words不一致，则返回错误                    if (temp_count[word] > word_count[word])                        break;                }//if                else{                    break;                }//else                             }//for            //所有words内的单词,在i起始位置都出现，则将下标i存入结果的vector中            if (j == word_nums)            {                ret.push_back(i);            }//if        }//for        return ret;    }};