<p>There is only one character <code>&#39;A&#39;</code> on the screen of a notepad. You can perform one of two operations on this notepad for each step:</p>

<ul>
	<li>Copy All: You can copy all the characters present on the screen (a partial copy is not allowed).</li>
	<li>Paste: You can paste the characters which are copied last time.</li>
</ul>

<p>Given an integer <code>n</code>, return <em>the minimum number of operations to get the character</em> <code>&#39;A&#39;</code> <em>exactly</em> <code>n</code> <em>times on the screen</em>.</p>

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

<pre>
<strong>Input:</strong> n = 3
<strong>Output:</strong> 3
<strong>Explanation:</strong> Initially, we have one character &#39;A&#39;.
In step 1, we use Copy All operation.
In step 2, we use Paste operation to get &#39;AA&#39;.
In step 3, we use Paste operation to get &#39;AAA&#39;.
</pre>

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

<pre>
<strong>Input:</strong> n = 1
<strong>Output:</strong> 0
</pre>

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

<ul>
	<li><code>1 &lt;= n &lt;= 1000</code></li>
</ul>

class Solution {
public:
    int minSteps(int n) {
        if (n == 1) return 0;
        int ret = 0;
        queue<vector<int>> buffer;
        set<int> flags;
        flags.insert(1000);
        buffer.push({1, 0});
        while (true) {
            ret++;
            int size = buffer.size();
            while (size != 0) {
                int now = buffer.front()[0];
                int copy = buffer.front()[1];
                buffer.pop();
                size--;

                if (copy != now) {
                    int id = now * 1000 + now;
                    if (flags.find(id) == flags.end()) {
                        buffer.push({now, now});
                        flags.insert(id);
                    }
                }

                if (copy != 0) {
                    if (now + copy == n) return ret;
                    if (now + copy > n) continue;
                    int id = (now + copy) * 1000 + copy;
                    if (flags.find(id) == flags.end()) {
                        buffer.push({now + copy, copy});
                        flags.insert(id);
                    }
                }
            }
        }
        return ret;
    }
};
34305