<p>In English, we have a concept called <strong>root</strong>, which can be followed by some other word to form another longer word - let&#39;s call this word <strong>derivative</strong>. For example, when the <strong>root</strong> <code>&quot;help&quot;</code> is followed by the word <code>&quot;ful&quot;</code>, we can form a derivative <code>&quot;helpful&quot;</code>.</p>

<p>Given a <code>dictionary</code> consisting of many <strong>roots</strong> and a <code>sentence</code> consisting of words separated by spaces, replace all the derivatives in the sentence with the <strong>root</strong> forming it. If a derivative can be replaced by more than one <strong>root</strong>, replace it with the <strong>root</strong> that has <strong>the shortest length</strong>.</p>

<p>Return <em>the <code>sentence</code></em> after the replacement.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> dictionary = [&quot;cat&quot;,&quot;bat&quot;,&quot;rat&quot;], sentence = &quot;the cattle was rattled by the battery&quot;
<strong>Output:</strong> &quot;the cat was rat by the bat&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> dictionary = [&quot;a&quot;,&quot;b&quot;,&quot;c&quot;], sentence = &quot;aadsfasf absbs bbab cadsfafs&quot;
<strong>Output:</strong> &quot;a a b c&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= dictionary.length &lt;= 1000</code></li>
	<li><code>1 &lt;= dictionary[i].length &lt;= 100</code></li>
	<li><code>dictionary[i]</code> consists of only lower-case letters.</li>
	<li><code>1 &lt;= sentence.length &lt;= 10<sup>6</sup></code></li>
	<li><code>sentence</code> consists of only lower-case letters and spaces.</li>
	<li>The number of words in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>The length of each word in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>Every two consecutive words in <code>sentence</code> will be separated by exactly one space.</li>
	<li><code>sentence</code> does not have leading or trailing spaces.</li>
</ul>

typedef struct Word_s {
    string word;
    bool flag;
} Word_t;

class Solution {
public:

    vector<Word_t> getWords(string str) {
        Word_t Wrd;
        vector<Word_t> words;
        string wrd = "";

        Wrd.word = "";
        Wrd.flag = false;


        for (int i=0;i<str.size();i++) {
            if (str[i] ==' ') {
                if (wrd != "") {
                    Wrd.word = wrd;
                    Wrd.flag = false;
                    words.push_back(Wrd);
                    wrd = "";
                }
            } else {
                wrd +=str[i];
            }
        }
        if (wrd != "") {
            Wrd.word = wrd;
            Wrd.flag = false;
            words.push_back(Wrd);
        }
        return words;
    }

    int rootExist(vector<Word_t> &wrds, vector<int>rep, string root) {
        int ret = 0;
        for (int i =0; i<wrds.size();i++) {
            //if (rep[i] == 0 && wrds[i].compare(0, root.size(), root) == 0) {
                //if (!wrds[i].flag && wrds[i].word.substr(0, root.size()) == root) {
            if (wrds[i].word.substr(0, root.size()) == root) {
                //wrds[i] = root;
                wrds[i].word = root;
                wrds[i].flag = true;
                //ret = i;
                //break;
                ret++;
            }
        }

        return ret;
    }
    string replaceWords(vector<string>& dictionary, string sentence) {
        string res;
        int cnt = 0;
        vector<int>replcs;
        auto words = getWords(sentence);      
        //replcs.resize(words.size());

        for (int i =0;i<words.size();i++) {
            replcs.push_back(0);
        }

        for (int i =0;i<dictionary.size();i++) {
                auto k = rootExist(words, replcs, dictionary[i]);
                if (k > 0 ) {
                    //words[k].replace(0, words[k].size(), dictionary[i]);
                    //replcs[k] = 1;
                    cnt += k;
                    if (cnt == words.size())
                        break;
                }
        }

        res = "";
        for (int i =0;i<words.size();i++) {
            if (i > 0) {
                res += " ";
            }
            res = res + words[i].word;
        }

        return res;
    }
};
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