杭电2024(C语言合法标识符)

import java.util.*;
class Main{
	public static void main(String args[]){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		sc.nextLine();
		while(n-->0 ){
			String str=sc.nextLine();
			if((str.charAt(0)>='a'&&str.charAt(0)<='z')||(str.charAt(0)>='A'&&str.charAt(0)<='Z')||(str.charAt(0)=='_')){
				int k=0;
				for(int i=1;i<str.length();i++){       
					if((str.charAt(i)>='a'&&str.charAt(i)<='z')||(str.charAt(i)>='A'&&str.charAt(i)<='Z')||(str.charAt(i)>='0'&&str.charAt(i)<='9')||(str.charAt(i)=='_'))
						k++;
				}
				if(k==(str.length()-1)){
					System.out.println("yes");   
				}else{
					System.out.println("no");
				}
			}else{
				System.out.println("no");
	 		}
		}
	}
}

Scanner sc1=new Scanner(System.in);
Scanner sc2=new Scanner(System.in);
while(sc1.hasNext()){
	int n=sc1.nextInt();
	while(n-->0 ){
		String str=sc2.nextLine();

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