<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>

class Solution {
public:

     struct TrieNode{
        TrieNode* suffix[26];

        bool isWordEnd;
        TrieNode(){
            isWordEnd = false;
            for(int i =0; i<26; i++){
                suffix[i] = NULL; 
            }
        }
    };

void insert(TrieNode* trie, string s)
        {
            char c;
            for(int i =0; i<s.length(); i++ ){
                c = s[i];
                if(trie->suffix[c-'a'] == NULL){
                    trie->suffix[c-'a'] = new TrieNode(); 
                }
                trie = trie->suffix[c-'a'];
            }
            trie->isWordEnd = true;
        }

    int findNode(TrieNode* trie, string s)
        {
            char c;
            int len = 0; 
           for(int i =0; i<s.length(); i++ ){
                c = s[i];
                if(trie->suffix[c-'a'] != NULL){

                    if(trie->isWordEnd)
                    return len;
                    len++;
                    trie = trie->suffix[c-'a'];
                }
                else if(trie->isWordEnd){
                    return len;
                }else
                {
                    break;
                }
            }
            if(trie->isWordEnd)
            return len;
            else{
                return 0;
            }
        }
   
    string replaceWords(vector<string>& dictionary, string sentence) {
        
        TrieNode* trie = new TrieNode(); 
        for(auto& it: dictionary){
            insert(trie, it);
        }

        vector<string> newSent;

        int pos = 0; 
        string str = sentence.substr(0, sentence.find(' '));
        while(str.length() >0 ){
           // cout<<str<<" "<<sentence<<endl;
            
            int len = findNode(trie, str);
            if(len > 0){
                cout<<"found "<<str<<" "<<len<<endl;
                newSent.push_back(str.substr(0, len));
            }else{
                newSent.push_back(str);
            }

            if(str!= sentence)
            sentence = sentence.substr(str.length() + 1);
            else{
                break;
            }
            pos = sentence.find(' ');
            //cout<<"pos "<<pos<<endl;
            if(pos > 0)
            str = sentence.substr(0, pos);
            else{
                str = sentence;
            }
        }

        string returnString;
        for(auto& it: newSent){
            returnString.append(it+ " ");
        }
        returnString = returnString.substr(0, returnString.length() -1);
       return returnString;
    }

};
377357