<p>Your car starts at position <code>0</code> and speed <code>+1</code> on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a sequence of instructions <code>&#39;A&#39;</code> (accelerate) and <code>&#39;R&#39;</code> (reverse):</p>

<ul>
	<li>When you get an instruction <code>&#39;A&#39;</code>, your car does the following:

	<ul>
		<li><code>position += speed</code></li>
		<li><code>speed *= 2</code></li>
	</ul>
	</li>
	<li>When you get an instruction <code>&#39;R&#39;</code>, your car does the following:
	<ul>
		<li>If your speed is positive then <code>speed = -1</code></li>
		<li>otherwise <code>speed = 1</code></li>
	</ul>
	Your position stays the same.</li>
</ul>

<p>For example, after commands <code>&quot;AAR&quot;</code>, your car goes to positions <code>0 --&gt; 1 --&gt; 3 --&gt; 3</code>, and your speed goes to <code>1 --&gt; 2 --&gt; 4 --&gt; -1</code>.</p>

<p>Given a target position <code>target</code>, return <em>the length of the shortest sequence of instructions to get there</em>.</p>

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

<pre>
<strong>Input:</strong> target = 3
<strong>Output:</strong> 2
<strong>Explanation:</strong> 
The shortest instruction sequence is &quot;AA&quot;.
Your position goes from 0 --&gt; 1 --&gt; 3.
</pre>

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

<pre>
<strong>Input:</strong> target = 6
<strong>Output:</strong> 5
<strong>Explanation:</strong> 
The shortest instruction sequence is &quot;AAARA&quot;.
Your position goes from 0 --&gt; 1 --&gt; 3 --&gt; 7 --&gt; 7 --&gt; 6.
</pre>

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

<ul>
	<li><code>1 &lt;= target &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
public:
    int racecar(int target) {
        queue<pair<long long,long long>> q;
        q.push({0,1});
        // q.push({0,-1});
        int level =0;
        set<pair<long long,long long>> s1 ;
        while(!q.empty())
        {
            int sz = q.size();
            while(sz--)
            {
                 auto it = q.front();
                 cout<<it.first<<" ";
                 if(it.first==target)
                 {
                     return level;
                 }
                 
                q.pop();
                if(s1.find({it.first,it.second})!=s1.end())
                {
                     continue;
                }
                else 
                {
                  if(it.first+it.second<=20003)
                 {
                  s1.insert({it.first,it.second});
                  q.push({it.first+it.second,it.second*2});
               
                  if((it.first+it.second>target and it.second>0) || (it.first+it.second<target and it.second<0))
                  {
                      if(it.second>0)
                      {
                         q.push({it.first,-1});
                      }
                      else if(it.second<0) 
                      {
                         q.push({it.first,1});
                      }
                   }
                 }
                }
               
            }
            cout<<endl;
            level++;
        }
        return -1;

    }
};
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