Longest Common Prefix

- -vector容器当为空的时候访问[]是直接出错的。

class Solution {
public:
string longestCommonPrefix(vector<string>& strs) {
string s = "";
if(strs.empty())
return s;
size_t len = strs[0].size();
for(size_t m = 0;m < strs.size();m++)
len = len < strs[m].size() ? len : strs[m].size();
for(size_t m = 0;m < len;m++){
for(size_t n = 0;n < strs.size();n++)
if(strs
[m] != strs[0][m])
return s;
s += strs[0][m];
}
return s;
}
};