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.empty())            return "";        int size = strs.size(), i, j;        if(size == 1)            return strs[0];        string ret = "";        sort(strs.begin(),strs.end());        int len = strs[0].length();//最短字符串长度        for(i = 0; i < len; ++i){            for(j = 1; j < size; ++j){                if(strs[j][i] != strs[j-1][i]){                    ret = strs[0].substr(0,i);                    return ret;                }            }        }        return strs[0];    }};