<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 solve(int n, int prevCopy, int currKeys,map<pair<int, int>, int> &mp) {
        if(currKeys == n) return 0;
        if(currKeys > n) return 1000;
        if(mp.find({prevCopy, currKeys}) != mp.end())
            return mp[{prevCopy, currKeys}];
        int copyPaste = 2 + solve(n, currKeys, 2*currKeys, mp);
        int paste = 1 + solve(n, prevCopy, currKeys+prevCopy, mp);
        return mp[{prevCopy, currKeys}] = min(copyPaste, paste);
    }
    int minSteps(int n) {
        if(n==1) return 0;
        map<pair<int, int>, int> mp;
        return 1 + solve(n, 1, 1, mp);
    }
};
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