<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 findPrefix(string str1, string str2) {
        string ans;
        
        int i = 0, j = 0;
        int n = str1.size(), m = str2.size();
        
        while (i < n && j < m) {
            if (str1[i] == str2[j]) {
                ans += str1[i];
                i++, j++;
            } else {
                break;
            }
        }
        
        return ans;
    }
    string longestCommonPrefix(vector<string>& strs) {
        if(strs.size()==0 )
        {
            return "";
        }
        if(strs.size()==1)
        {
            return strs[0];
        }
        string prefix = findPrefix(strs[0],strs[1]);
        for(int i=0;i<strs.size()-1;i++)
        {
            string pre = findPrefix(strs[i],strs[i+1]);
            prefix= findPrefix(pre,prefix);
        }
        
        return prefix;
    }
};
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