14. Longest Common Prefix java solutions

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

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(strs == null || strs.length == 0) return "";
        String ans = strs[0];
        int len = strs[0].length();
        for(int i = 1; i < strs.length; i++){
            len = Math.min(len,strs[i].length());//与后面的字符串进行比较的时候，取len 小的
            while(len > 0 && !strs[0].substring(0,len).equals(strs[i].substring(0,len))) len --;
            if(len == 0){
                ans = "";
                return ans;
            }
            ans = strs[0].substring(0,len);
        }
        return ans;
    }
}