Longest Common Prefix

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

class Solution {public:    string longestCommonPrefix(vector<string> &strs) {    if(strs.size()==0)    {        return  "";    }        if(strs.size()==1)    {        return  strs[0];    }        string strTemp=strs[0];string s1=strTemp,s2;string strCommon;int i;vector<string>::iterator iter=strs.begin();++iter;for(;iter!=strs.end();++iter){        s2=*iter;int n=min(s1.length(),s2.length());for(i=1;i<=n;){           if(s1.substr(0,i)==s2.substr(0,i))   {   ++i;   }   else   {   break;   }}        strCommon=s1.substr(0,i-1);if(strCommon.empty()){           return strCommon;}s1=strCommon;}return strCommon;            }};