<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 longestCommonPrefix(vector<string>& strs) {
        string pre="";
        bool common = true;
        int size = 0;
        while(common)
        {   
            // cout<<strs[0]<<" ";
            char letter;
            if (strs[0]=="")
            {
                common=false;
                break;
            }
            else
            {   
                letter = strs[0][0];
                strs[0] = strs[0].substr(1);
            }
            if (!common) break;
            for(int i=1;i<strs.size();i++)
            {
                // if (strs[i].length()<size || strs[i][size]!=strs[i-1][size] ||strs[i-1].length()<size )
                // {
                //     common=false;
                //     break;
                // }
                // cout<<strs[i]<<" ";
                if (strs[i]=="" || strs[i][0]!=letter)
                {
                    common=false;
                    break;
                }
                else
                {
                    strs[i] = strs[i].substr(1);
                }
            }
            // cout<<"\n";
            if (!common) break;
            
            pre+=letter;
            // size++;
        }
        return pre;
    }
};
15000