14. Longest Common Prefix

简单的直接上代码：

public  int findMin(String[] str){if(str.length==0){return -1;}int a=str[0].length(),b,c=0;for(int i = 0 ; i <str.length;i++){b=str[i].length();if(b==0){return -1;}if(a>b){a=b;c=i;}}System.out.println(c);return c;}public  String longestCommonPrefix(String[] str){ StringBuilder sb=new StringBuilder();int min=findMin(str);if(min==-1){return "";}for(int i=0;i<str[min].length();i++){for(int j= 0 ; j<str.length;j++){if(str[min].charAt(i)==str[j].charAt(i)){if(j==str.length-1){sb.append(str[j].charAt(i));}}else {return sb.toString();}}}return sb.toString();}

运行时间18ms