<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:
    long long int solve(int index, vector<string>& stickers, long long int n, string target,long long int state, vector<vector<long long int>>& dp){
        if(state == (1<<target.size())-1) return 0;
        if(index == stickers.size()) return INT_MAX;
        if(dp[index][state] != -1) return dp[index][state];

        vector<int> data(27,0);
        for(int i=0;i<stickers[index].size();i++){
            data[stickers[index][i] - 'a']++;
        }

        int newState = state;
        for(int i=0;i<target.size();i++){
            if(((newState>>i) & 1) == 0){
                if(data[target[i] - 'a']>0){
                    data[target[i] - 'a']--;
                    newState = newState | (1<<i);
                }
            }
        }

        long long int ans = INT_MAX;
        ans = min(ans, solve(index+1,stickers,n,target,state,dp));

        if(state != newState){
            ans = min(ans,1 + solve(index,stickers,n,target,newState,dp));
        }
        return dp[index][state] = ans;
    }
    int minStickers(vector<string>& stickers, string target) {
        vector<vector<long long int>> dp(stickers.size(), vector<long long int>((1<<target.size()), -1));
        long long int n = stickers.size();
        long long int ans = solve(0, stickers, n, target, 0, dp);
        return ans == INT_MAX ? -1 : ans;
    }
};
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