<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>

struct Trie {
    Trie *next[128];
    bool end;
    Trie(){
        end=false;
        for(int i=0;i<128;i++){
            next[i]=NULL;
        }
    }
};

class Solution {
public:
    string replaceWords(vector<string>& dictionary, string sentence) {
        Trie *t=new Trie();
        for(auto &w:dictionary){
            auto tmp=t;
            for(auto &c:w){
                if(!tmp->next[c]){
                    tmp->next[c]=new Trie();
                }
                tmp=tmp->next[c];
            }
            tmp->end=true;
        }
        vector<string> split;
        string str;
        for(int i=0;i<=sentence.size();i++){
            if(sentence[i]==' '||sentence[i]=='\0'){
                if(str.size()>0){
                    split.push_back(str);
                }
                str="";
            }else{
                str+=sentence[i];
            }
        }
        string ret;
        for(int i=0;i<split.size();i++){
            auto tmp=t;
            str="";
            for(auto &c:split[i]){
                if(!tmp->next[c]){
                    str=split[i];
                    break;
                }
                tmp=tmp->next[c];
                str+=c;
                if(tmp->end){
                    break;
                }
            }
            ret+=str;
            if(i!=split.size()-1){
                ret+=" ";
            }
        }
        return ret;
    }
};
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