<p>Given a string <code>s</code> and a dictionary of strings <code>wordDict</code>, return <code>true</code> if <code>s</code> can be segmented into a space-separated sequence of one or more dictionary words.</p>

<p><strong>Note</strong> that the same word in the dictionary may be reused multiple times in the segmentation.</p>

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

<pre>
<strong>Input:</strong> s = &quot;leetcode&quot;, wordDict = [&quot;leet&quot;,&quot;code&quot;]
<strong>Output:</strong> true
<strong>Explanation:</strong> Return true because &quot;leetcode&quot; can be segmented as &quot;leet code&quot;.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;applepenapple&quot;, wordDict = [&quot;apple&quot;,&quot;pen&quot;]
<strong>Output:</strong> true
<strong>Explanation:</strong> Return true because &quot;applepenapple&quot; can be segmented as &quot;apple pen apple&quot;.
Note that you are allowed to reuse a dictionary word.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;catsandog&quot;, wordDict = [&quot;cats&quot;,&quot;dog&quot;,&quot;sand&quot;,&quot;and&quot;,&quot;cat&quot;]
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 300</code></li>
	<li><code>1 &lt;= wordDict.length &lt;= 1000</code></li>
	<li><code>1 &lt;= wordDict[i].length &lt;= 20</code></li>
	<li><code>s</code> and <code>wordDict[i]</code> consist of only lowercase English letters.</li>
	<li>All the strings of <code>wordDict</code> are <strong>unique</strong>.</li>
</ul>

class TrieNode {
public:
    TrieNode *child[26];
    bool isWord;
    char ch;
    TrieNode() {
        isWord = false;
        for (auto &a : child) a = NULL;
    }
};
class Solution {
public:
    TrieNode* root;
    void insert(string word) {
        TrieNode* temp = root;
        for(auto i : word) {
            int index = i-'a';
            if(temp->child[index] == NULL) {
                temp->child[index] = new TrieNode();
            }

            temp = temp->child[index];
        }
        temp->isWord = true;
    }
    bool search(string str) {
        TrieNode* temp = root;
       
        for(auto i : str) {
            int index = i-'a';
            if(temp->child[index] == NULL) {
                return false;
            }    
                temp = temp->child[index];
        }
        return (temp->isWord);
    }
    bool wordBreak(string s, vector<string>& wordDict) {
        root = new TrieNode();
        for(auto str : wordDict)
            insert(str);
        int n = s.length();
        vector<bool> res(n+1, false);
        res[0] = true;
        for(int j = 1; j <= n; j++) {
            for(int i = 0; i<j; i++) {
                string ptr = s.substr(i,j-i);
                if(res[i] && search(ptr)) {
                    res[j] = true;
                     break;
                }     
            }
        }
        return res[n];
    }  
    
};
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