Longest Common Prefix

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

查找最长公共前缀。

class Solution {public:    string longestCommonPrefix(vector<string>& strs) {                if (strs.size() == 0)   //数组长度为0，返回空            return "";                    string preStr = strs[0];        for (int i = 1;i < strs.size(); i++){            if(preStr.length() == 0 || strs[i].length() == 0){                return "";            }                        int j = 0;            string tempStr = "";            while(j<preStr.length() && j<strs[i].length()){                if(preStr[j] == strs[i][j]){                    tempStr += preStr[j];                    j++;                }else{                    break;                }            }            preStr = tempStr;        }        return preStr;    }};