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:
public String replaceAll(String regex, String replacement)
Replaces each substring of this string that matches the given
regular expression with 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。