回文字符串

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String str = sc.nextLine();
            StringBuilder sb = new StringBuilder(str);
            if(sb.toString().equals(sb.reverse().toString())){
                System.out.println("Yes!");
            }else{
                System.out.println("No!");
            }
        }
    }
}

用Eclipse完全没错，提交到网站却出错······

public class Main {
	
	public void doSome(String string){
		if(string.length()%2!=0){
			int record1=0;
			for(int i=0;i<string.length()/2;i++){
				if(string.charAt(i)==string.charAt(string.length()-i-1)){
					record1++;
				}
			}
			if(record1==string.length()/2){
				System.out.println("Yes!");
			}else{
				System.out.println("No!");
			}
		}else{
			int record2=0;
			for(int i=0;i<=string.length()/2-1;i++){
				if(string.charAt(i)==string.charAt(string.length()-i-1)){
					record2++;
				}
			}
			if(record2==string.length()/2){
				System.out.println("Yes!");
			}else{
				System.out.println("No!");
			}
		}
	}

	public static void main(String[] args) {
		Scanner s=new Scanner(System.in);
		String input;
		Main m=new Main();
		while(true){
			input=s.nextLine();
			m.doSome(input);
		}
	}
}

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    while(sc.hasNext()){
        String s=sc.nextLine();
        boolean b=true;
        for(int i=0;i<s.length()/2;i++){
            if(s.charAt(i)!=s.charAt(s.length()-1-i)){
                b=false;
                break;
            }
        }
        if(b){
            System.out.println("Yes!");
        }else{
            System.out.println("No!");
        }
    }
    sc.close();
}

}

}//头尾同时比较即可

}

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner in=new Scanner(System.in);
        while(in.hasNext()){
            String str=in.nextLine();
            StringBuilder sb=new StringBuilder(str);
            String s=sb.reverse().toString();
            if(str.equals(s))
            System.out.println("Yes!");
            else
            System.out.println("No!");
        }
    }
}

public class Main {

public static void main(String[] args) {

String a = null;

StringBuffer sb = null;

Scanner in = new Scanner(System.in);

while(in.hasNext()){

a = in.nextLine();

sb = new StringBuffer(a);

sb = sb. reverse() ;

if(a.compareTo(sb.toString()) == 0)

System.out.println("Yes!");

else

System.out.println("No!");

}

in.close();

}