<p>Strings <code>s1</code> and <code>s2</code> are <code>k</code><strong>-similar</strong> (for some non-negative integer <code>k</code>) if we can swap the positions of two letters in <code>s1</code> exactly <code>k</code> times so that the resulting string equals <code>s2</code>.</p>

<p>Given two anagrams <code>s1</code> and <code>s2</code>, return the smallest <code>k</code> for which <code>s1</code> and <code>s2</code> are <code>k</code><strong>-similar</strong>.</p>

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

<pre>
<strong>Input:</strong> s1 = &quot;ab&quot;, s2 = &quot;ba&quot;
<strong>Output:</strong> 1
<strong>Explanation:</strong> The two string are 1-similar because we can use one swap to change s1 to s2: &quot;ab&quot; --&gt; &quot;ba&quot;.
</pre>

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

<pre>
<strong>Input:</strong> s1 = &quot;abc&quot;, s2 = &quot;bca&quot;
<strong>Output:</strong> 2
<strong>Explanation:</strong> The two strings are 2-similar because we can use two swaps to change s1 to s2: &quot;abc&quot; --&gt; &quot;bac&quot; --&gt; &quot;bca&quot;.
</pre>

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

<ul>
	<li><code>1 &lt;= s1.length &lt;= 20</code></li>
	<li><code>s2.length == s1.length</code></li>
	<li><code>s1</code> and <code>s2</code> contain only lowercase letters from the set <code>{&#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, &#39;e&#39;, &#39;f&#39;}</code>.</li>
	<li><code>s2</code> is an anagram of <code>s1</code>.</li>
</ul>

class Solution {
    vector<string> getvect(string t,string s2){
        int n=t.size();
        int i=0;
        while(t[i]==s2[i]){
            i++;
        }
        vector<string> temp;
        for(int k=i+1;k<n;k++){
            if(t[k]==s2[i]){
                swap(t[i],t[k]);
                temp.push_back(t);
                swap(t[i],t[k]);
            }
        }
        return temp;
    }
public:
    int kSimilarity(string s1, string s2) {
        int n=s1.size();
        queue<string> q;
        map<string,int> mp;//to keep track that eleemnt wont repeat and it 
        //to maintain their level or swap count you can say as at each level 1 swap is taking 
        q.push(s1);
        mp.insert({s1,0});
        while(q.size()>0){
            string t=q.front();
            q.pop();
            if(t==s2){
                return mp[t];
            }
            else{
                vector<string> temp=getvect(t,s2);
                for(int i=0;i<temp.size();i++){
                    if(mp.count(temp[i])==0){
                        q.push(temp[i]);
                        mp.insert({temp[i],mp[t]+1});
                    }
                }
            }
        }
        return -1;


        /*
        int n=s1.size();
        int m=s2.size();
        int i=0;
        int j=n-1;
        int count=0;
        while( i<n && i<j){
            if(i<n && s1[i]==s2[i]){
                i++;
            }
            if(j>i && s1[j]==s2[j]){
                j--;
            }

            if(i==n || i==j){
                break;
            }
            if(s1[i]!=s2[i] && s1[j]!=s2[j]){
                count++;
                swap(s1[i],s1[j]);
            }
            else{
                count=-1;
                break;
            }
        }
        return count;
        */
        
    }
};
170039