代码勇士真题：
给定一个字符串由a-z字母组成的字符串s，长度任意字母可任意组合。
要求编写函数找出s中不在a-m范围内的字母个数n，要求函数返回字符串格式为：n/s的长度
例如：
s="aaabbbbhaijjjm"error_printer(s) => "0/14"s="aaaxbbbbyyhwawiwjjjwwm"error_printer(s) => "8/22"
public class Printer {public static String printerError(String s) {if(s.length()==0){return "";}else{StringBuffer pattern = new StringBuffer("abcdefghijklm");char[] chr = s.toCharArray();int errorCount=0;for(char c:chr){if(pattern.indexOf(String.valueOf(c))<0){errorCount++;}}//return "\""+errorCount+"/"+s.length()+"\"";return String.format("%d/%d",errorCount,s.length());}}public static String printerErrorBest(String s) {return s.replaceAll("[a-m]", "").length() + "/" + s.length();}public static void main(String[] args) {System.out.println(printerError("aaabbbbhaijjjm"));}}
说明：
publicStringreplaceAll(Stringregex,Stringreplacement)
Replaces each substring of this string that matches the givenregular expressionwith the given replacement.
使用replacement参数替换源字符串中所有满足正则表达式的子字符串。
