LeetCode OJ：Longest Common Prefix（最长公共前缀）

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

求很多string的公共前缀，用个两重循环就可以，代码如下：

 class Solution {
 public:
     string longestCommonPrefix(vector<string>& strs) {
         string prefix;
         if(strs.size() ==  || strs[].size() == )
             return "";
         int start = ;
         bool endLoop = false;
         char cmp = strs[][];
         while(true && !endLoop){
             cout << cmp << endl;
             for(int i = ; i < strs.size(); ++i){
                 if(start >= strs[i].size() || cmp != strs[i][start]){
                     endLoop = true;
                     break;
                 }
             }
             if(!endLoop){
                 start++;
                 if(start < strs[].size())
                     cmp = strs[][start];
             }

         }
         return strs[].substr(, start - );
     }
 };