学步园

回头看，当时好像是为了练手写Java，刷题

import java.util.*;<br /> public class Main {<br /> //http://acm.hdu.edu.cn/showproblem.php?pid=2024<br /> public static void main(String[] args) {<br /> Scanner sc = new Scanner(System.in);<br /> int cnt = sc.nextInt();<br /> WordCheck wc = new WordCheck();<br /> String str = sc.nextLine();<br /> for(int i=0; i<cnt; ++i){<br /> str = sc.nextLine();<br /> if(wc.isOk(str)){<br /> System.out.println("yes");<br /> }else{<br /> System.out.println("no");<br /> }<br /> }<br /> }<br /> }<br /> class WordCheck{<br /> public WordCheck(){}<br /> boolean isNumber(char c){<br /> if(c >= '0' && c <= '9')<br /> return true;<br /> return false;<br /> }<br /> boolean isAlpha(char c){<br /> if(c >= 'A' && c <= 'z')<br /> return true;<br /> return false;<br /> }<br /> boolean isUnderline(char c){<br /> if(c == '_')<br /> return true;<br /> return false;<br /> }<br /> boolean isOk(String str){<br /> if(!(isUnderline(str.charAt(0)) || isAlpha(str.charAt(0)))){<br /> return false;<br /> }<br /> for(int i=1; i<str.length(); ++i){<br /> if(!(isUnderline(str.charAt(i)) || isAlpha(str.charAt(i))<br /> || isNumber(str.charAt(i))))<br /> return false;<br /> }<br /> return true;<br /> }<br /> }