最长公共前缀

 1 /**
 2  * @param {string[]} strs
 3  * @return {string}
 4  */
 5 var longestCommonPrefix = function(strs) {
 6 if(strs.length === 0) return "";
 7 let ans = strs[0];
 8 for(let i = 0; i < strs.length; i++){
 9     let j =0;
10     for(; j < ans.length && j < strs[i].length; j++){
11         if(ans[j] !== strs[i][j]) break;
12     }
13     ans = ans.substr(0, j);
14     if(ans === "") return ans;
15 }
16 return ans;
17 };