https://leetcode.com/problems/longest-common-prefix/
class Solution {
public:
string longestCommonPrefix(vector<string>& strs) {
int n=0;
if ( strs.size()==0 )
return "";
if ( strs.size()==1 )
return strs[0] ;
for (int i=0; i< strs[0].size();i++)
{
char temp=strs[0][i];
for (int j=1; j<strs.size();j++)
{
if ( temp !=strs[j][i] )
{
return strs[j].substr(0,i);
}
}
}
return strs[0];
}
};