<p>We are given <code>n</code> different types of <code>stickers</code>. Each sticker has a lowercase English word on it.</p>

<p>You would like to spell out the given string <code>target</code> by cutting individual letters from your collection of stickers and rearranging them. You can use each sticker more than once if you want, and you have infinite quantities of each sticker.</p>

<p>Return <em>the minimum number of stickers that you need to spell out </em><code>target</code>. If the task is impossible, return <code>-1</code>.</p>

<p><strong>Note:</strong> In all test cases, all words were chosen randomly from the <code>1000</code> most common US English words, and <code>target</code> was chosen as a concatenation of two random words.</p>

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

<pre>
<strong>Input:</strong> stickers = [&quot;with&quot;,&quot;example&quot;,&quot;science&quot;], target = &quot;thehat&quot;
<strong>Output:</strong> 3
<strong>Explanation:</strong>
We can use 2 &quot;with&quot; stickers, and 1 &quot;example&quot; sticker.
After cutting and rearrange the letters of those stickers, we can form the target &quot;thehat&quot;.
Also, this is the minimum number of stickers necessary to form the target string.
</pre>

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

<pre>
<strong>Input:</strong> stickers = [&quot;notice&quot;,&quot;possible&quot;], target = &quot;basicbasic&quot;
<strong>Output:</strong> -1
Explanation:
We cannot form the target &quot;basicbasic&quot; from cutting letters from the given stickers.
</pre>

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

<ul>
	<li><code>n == stickers.length</code></li>
	<li><code>1 &lt;= n &lt;= 50</code></li>
	<li><code>1 &lt;= stickers[i].length &lt;= 10</code></li>
	<li><code>1 &lt;= target.length &lt;= 15</code></li>
	<li><code>stickers[i]</code> and <code>target</code> consist of lowercase English letters.</li>
</ul>

class Solution {
public:
    int solve(int i,int mask,vector<vector<int>> &dp,vector<string>& s, string t){
        if(mask+1==(1<<(t.size())))
            return 0;
        if(i==s.size()){
            return 1e4;
        }
        if(dp[i][mask]!=-1)
        return dp[i][mask];
        vector<int> m(26);
        int tempMask = mask;
        for(auto b:s[i]){
        m[b-'a']++;
        }

        for(int k=0;k<t.size();k++){
            if(!((1<<k)&mask) && m[t[k]-'a']){
                m[t[k]-'a']--;
                tempMask|=(1<<k);
            }
        }
        int ans = solve(i+1,mask,dp,s,t);
        // return ans;
        if(mask!=tempMask)
        ans = min(ans,1+solve(i,tempMask,dp,s,t));
        return dp[i][mask] = ans;
    }
    int minStickers(vector<string>& stickers, string target) {
        vector<vector<int>>dp(stickers.size(),vector<int>(1<<(target.size()+1),-1));
        int ans = solve(0,0,dp,stickers,target);
        if(ans==1e4)
        ans = -1;
        return ans;
    }
};
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