<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 compare_prefixes(string s1, string s2){
        int c=0, min;
        int n1 = s1.size(), n2 = s2.size();
        string minstr, maxstr;
        if (n1<n2){
            minstr = s1;
            maxstr = s2;
            min = n1;
        }
        else{
            minstr = s2;
            maxstr = s1;
            min = n2;
        }
        if (min==0){
            return "";
        }
        for (int i=0;i<min;i++){
            if (minstr[i]==maxstr[i])
                c++;
            else
                break;
        }
        return maxstr.substr(0,c);
    }
    string longestCommonPrefix(vector<string>& strs) {
        string x=strs[0];
        for (int i=1;i<strs.size();i++){
            x = compare_prefixes(x,strs[i]);
        }
        return x;
    }
};
12400