<p>Write a function to find the longest common prefix string amongst an array of strings.</p>

<p>If there is no common prefix, return an empty string <code>&quot;&quot;</code>.</p>

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

<pre>
<strong>Input:</strong> strs = [&quot;flower&quot;,&quot;flow&quot;,&quot;flight&quot;]
<strong>Output:</strong> &quot;fl&quot;
</pre>

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

<pre>
<strong>Input:</strong> strs = [&quot;dog&quot;,&quot;racecar&quot;,&quot;car&quot;]
<strong>Output:</strong> &quot;&quot;
<strong>Explanation:</strong> There is no common prefix among the input strings.
</pre>

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

<ul>
	<li><code>1 &lt;= strs.length &lt;= 200</code></li>
	<li><code>0 &lt;= strs[i].length &lt;= 200</code></li>
	<li><code>strs[i]</code> consists of only lowercase English letters.</li>
</ul>

class Solution {
public:
    string longest(string& str,string& str1){
        int i=0;
        int j = 0;
        string s = "";

        while(i<str.length() && j<str1.length()){
            if(str[i]==str1[j]){
                s = s + str[i];
                i++;
                j++;
            }
            else{
                break;
            }
        }

        return s;
    }
    string longestCommonPrefix(vector<string>& strs) {

        if(strs.size()==1){
            return strs[0];
        }
        string str = strs[0];
        string str2 = "";

        for(int i=1;i<strs.size();i++){

            string str1 = strs[i];

            str2 = longest(str,str1);

            str = str2;
        }

        return str2;
    }
};
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