<p>Given two strings <code>s1</code> and <code>s2</code>, return <code>true</code><em> if </em><code>s2</code><em> contains a permutation of </em><code>s1</code><em>, or </em><code>false</code><em> otherwise</em>.</p>

<p>In other words, return <code>true</code> if one of <code>s1</code>&#39;s permutations is the substring of <code>s2</code>.</p>

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

<pre>
<strong>Input:</strong> s1 = &quot;ab&quot;, s2 = &quot;eidbaooo&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> s2 contains one permutation of s1 (&quot;ba&quot;).
</pre>

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

<pre>
<strong>Input:</strong> s1 = &quot;ab&quot;, s2 = &quot;eidboaoo&quot;
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= s1.length, s2.length &lt;= 10<sup>4</sup></code></li>
	<li><code>s1</code> and <code>s2</code> consist of lowercase English letters.</li>
</ul>

class Solution {


public:
    bool checkInclusion(string s1, string s2) {
        if(s1.size() > s2.size()){
            return false;
        }


        std::unordered_map<char, int> lettersMap, isLetterPresent;
        int totalNumberOfLetters = 0;


        for (char c : s1){
            if(lettersMap.find(c)==lettersMap.end()){
                lettersMap[c] = 1;
            }else{
                lettersMap[c]++;
            }
            totalNumberOfLetters++;
        }

        // std::cout << "*************************" << std::endl;
        // for(std::unordered_map<char, int>::iterator iter =  lettersMap.begin(); iter != lettersMap.end(); ++iter){
        //     std::cout << "letter: " << iter->first << " number: " << iter->second << std::endl;
        // }
        // std::cout << "*************************" << std::endl;

        // int currentStringBeginningIndex = 0;
        for (int i=0; i < s2.size()-s1.size()+1; i++){
            // std::cout << "CURRENT LETTER " << s2[i] << std::endl;

            int numberOfCurrentLetters=0;
            for(int currentIndex=i; currentIndex<s2.size() && numberOfCurrentLetters<totalNumberOfLetters; currentIndex++){
                // std::cout << "current lettre " << s2[currentIndex] << std::endl;
                // std::cout << "currentIndex " << currentIndex << std::endl;

                if(lettersMap.find(s2[currentIndex])!=lettersMap.end() ){
                    if(isLetterPresent.find(s2[currentIndex])==isLetterPresent.end() ){
                        // std::cout << "adding lettre: " << s2[currentIndex] << " to isLetterPresent" << std::endl;
                        isLetterPresent[s2[currentIndex]] = 1;
                        numberOfCurrentLetters++;
                    }
                    else if (lettersMap[s2[currentIndex]] > isLetterPresent[s2[currentIndex]]){
                        // std::cout << "incrementing counter for  " << s2[currentIndex]  << std::endl;
                        isLetterPresent[s2[currentIndex]]++;
                        numberOfCurrentLetters++;
                    }else{
                        // std::cout << "resetting and continuing... " << std::endl;
                        numberOfCurrentLetters=0;
                        isLetterPresent.clear();
                        break;
                    }

                    if (numberOfCurrentLetters == totalNumberOfLetters){
                        // std::cout << "returning TRUE " << std::endl;
                        return true;
                    }

                } else {
                    // std::cout << "resetting and continuing... " << std::endl;
                    numberOfCurrentLetters=0;
                    isLetterPresent.clear();
                    break;

                }

            }

        }
        return false;
    }
};
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