Write a function to find the longest common prefix string amongst an array of strings.
Solution:
1 class Solution { 2 public: 3 string longestCommonPrefix(vector<string>& strs) { //runtime:4ms 4 string str=""; 5 if(strs.empty())return str; 6 int index=0; 7 8 while(true){ 9 if(index>=strs[0].size())return str; 10 char c=strs[0][index]; 11 for(int i=1;i<strs.size();i++){ 12 if(index>=strs[i].size()||strs[i][index]!=c)return str; 13 } 14 str+=c; 15 index++; 16 } 17 18 } 19 };