LeetCode-1078-Bigram-分词

2021-12-26

题目

给出第一个词 first 和第二个词 second，考虑在某些文本 text 中可能以 “first second third” 形式出现的情况，其中 second 紧随 first 出现，third 紧随 second 出现。

对于每种这样的情况，将第三个词 “third” 添加到答案中，并返回答案。

示例

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输入：text = "alice is a good girl she is a good student", first = "a", second = "good"
输出：["girl","student"]

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输入：text = "we will we will rock you", first = "we", second = "will"
输出：["we","rock"]

解答

根据题意进行模拟

代码

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vector<string> findOcurrences(string text, string first, string second) {
        vector<string> words;
        int s = 0, e = 0, len = text.length();
        while (true) {
            while (s < len && text[s] == ' ') {
                s++;
            }
            if (s >= len) {
                break;
            }
            e = s + 1;
            while (e < len && text[e] != ' ') {
                e++;
            }
            words.push_back(text.substr(s, e - s));
            s = e + 1;
        }
        vector<string> ret;
        for (int i = 2; i < words.size(); i++) {
            if (words[i - 2] == first && words[i - 1] == second) {
                ret.push_back(words[i]);
            }
        }
        return ret;
   }

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 vector<string> findOcurrences(string text, string first, string second) {
        stringstream ss(text);
        string str;
        vector<string> strs;
        while (ss >> str) {
            strs.push_back(str);
        }
        
        vector<string> ans;
        for (int i = 0; i + 2 < strs.size(); i ++) {
            if (strs[i] == first && strs[i + 1] == second) {
                ans.push_back(strs[i + 2]);
            }
        }
        return ans;
    }

#简单