<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 minStickers(vector<string>& stickers, string target) {
        unordered_map<char, int> target_map;
        unordered_map<string, int> visited;
        for (auto c: target) {
            bool found = false;
            for (auto str: stickers) {
                if (str.find(c) != std::string::npos) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                return -1;
            }
        }

        queue<pair<string, int>> bfs_queue;
        string start_str(target.size(), '0');
        visited[start_str] = 0;
        bfs_queue.push({start_str, 0});
        while (!bfs_queue.empty()) {
            string cur_origin = bfs_queue.front().first;
            int cur_dist = bfs_queue.front().second;
            bfs_queue.pop();
            for (auto sticker: stickers) {
                string cur_str = cur_origin;
                unordered_map<char, int> sticker_map;
                for (auto c: sticker) {
                    sticker_map[c]++;
                }
                for (int i = 0; i < target.size(); i++) {
                    if (cur_str[i] == '1') {
                        continue;
                    }
                    if (sticker_map[target[i]] > 0) {
                        sticker_map[target[i]]--;
                        cur_str[i] = '1';
                    }
                }
                // cout << "cur_str is " << cur_str << "\n";
                // cout << "sticker is " << sticker << "\n";
                if (visited.count(cur_str) > 0) {
                    continue;
                }
                visited[cur_str] = 1;

                bool is_complete = true;
                for (auto c: cur_str) {
                    if (c == '0') {
                        is_complete = false;
                    }
                }
                if (is_complete) {
                    return cur_dist + 1;
                }
                // cout << "cur_str is " << cur_str << "\n";
                // cout << "sticker is " << sticker << "\n";
                bfs_queue.push({cur_str, cur_dist + 1});
            }
        }
        return -2;

    }
};
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