<p>You are given a <strong>0-indexed</strong> string <code>s</code> and a dictionary of words <code>dictionary</code>. You have to break <code>s</code> into one or more <strong>non-overlapping</strong> substrings such that each substring is present in <code>dictionary</code>. There may be some <strong>extra characters</strong> in <code>s</code> which are not present in any of the substrings.</p>

<p>Return <em>the <strong>minimum</strong> number of extra characters left over if you break up </em><code>s</code><em> optimally.</em></p>

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

<pre>
<strong>Input:</strong> s = &quot;leetscode&quot;, dictionary = [&quot;leet&quot;,&quot;code&quot;,&quot;leetcode&quot;]
<strong>Output:</strong> 1
<strong>Explanation:</strong> We can break s in two substrings: &quot;leet&quot; from index 0 to 3 and &quot;code&quot; from index 5 to 8. There is only 1 unused character (at index 4), so we return 1.

</pre>

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

<pre>
<strong>Input:</strong> s = &quot;sayhelloworld&quot;, dictionary = [&quot;hello&quot;,&quot;world&quot;]
<strong>Output:</strong> 3
<strong>Explanation:</strong> We can break s in two substrings: &quot;hello&quot; from index 3 to 7 and &quot;world&quot; from index 8 to 12. The characters at indices 0, 1, 2 are not used in any substring and thus are considered as extra characters. Hence, we return 3.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 50</code></li>
	<li><code>1 &lt;= dictionary.length &lt;= 50</code></li>
	<li><code>1 &lt;= dictionary[i].length &lt;= 50</code></li>
	<li><code>dictionary[i]</code>&nbsp;and <code>s</code> consists of only lowercase English letters</li>
	<li><code>dictionary</code> contains distinct words</li>
</ul>

class Solution {
    int fun(int ind,unordered_set<string>&st,string s,vector<int>&dp){
        
        if(ind == s.size()){
            return 0;
        }

        if(dp[ind]!=-1){
            return dp[ind];
        }

        
        int take=0,nottake=0;
        // for(int i=ind;i<s.size();i++){
        //     string tmp = "";
        //     for(int j=ind;j<=i;j++){
        //         tmp+=s[j];
        //     }
        //     if(st.find(tmp)!=st.end()){
        //         take = (i-ind+1) + fun(i+1,st,s,dp);
        //     }
            
        // }
        // nottake=fun(ind+1,st,s,dp);
        // return dp[ind]=max(nottake,take);

        int ans=1e9;

        for(int j=ind;j<s.size();j++)
        {
            //substring ind->j

            string tmp=s.substr(ind,j-ind+1);

            if(st.count(tmp))
            {
                ans=min(ans,fun(j+1,st,s,dp));
            }
            else
            {
                ans=min(ans,int(tmp.size())+fun(j+1,st,s,dp));
            }
        }
        return  dp[ind]=ans;
    }
public:
    int minExtraChar(string s, vector<string>& d) {
        unordered_set<string>st;
        for(auto i : d){
            st.insert(i);
        }
        vector<int>dp(s.size()+1,-1);
        return fun(0,st,s,dp);

       
    }
};
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