Leetcode: Longest Common Prefix

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

string longestCommonPrefix(vector<string> &strs) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        int row = strs.size();if(row < 1) return "";if(row == 1) return strs[0];int strlength = strs[0].length();for(int i = 1; i < row; ++i)if(strs[i].length() < strlength) strlength = strs[i].length();int count = 0;bool flag = true;for(int i=0; i< strlength && flag; ++i){char commonchar = strs[0][count];int j = 0;for(; j < row; ++j)if(strs[j][count] != commonchar)    {flag = false; break;}if((j == row) && (flag = true))count++;}return strs[0].substr(0,count);    }