实现回文字符串判断 -- JAVA 算法学习

大一的时候老师上课的经典例子就是回文字符串判断，我觉得经典，也保留了下来。

很简单的判断，即字符串从前往后输出和从后往前输出都是一样的结果。是不是想到了什么，没错，就是栈(FIFO)，用这个就可以很好的解决这个问题啦~

public class HuiWenString {

       public String isHuiWen(String string ){

             int mid ;

             int top =0;

             char [] charOne ;

             if ( string .length()==1)

                   return "Yes" ;

                   mid = string .length()/2;

             charOne = new char [ mid ];

            //System. out .println( "mid=" + mid );

             for ( int i = 0; i < mid ; i ++){

                   charOne [ i ]= string .charAt( i );

                   top ++;

            }

             top --;

                   //charOne[top] = string.charAt(top);

                   //charOne[i-1] = string.charAt(i-1);

           //System. out .println( "top=" + top );

           //  for ( int i =0; i < charOne . length ; i ++)

            //System. out .println( "char=" + charOne [ i ]);

             if ( string .length()%2==0){

                  System. out .println( "s-mid=" + string .charAt( mid )+ "c-top=" + charOne [ top ]);

                  System. out .println( string .charAt( mid )!= charOne [ top ]);

                   if ( string .charAt( mid )!= charOne [ top ]){

                         return "NO1" ;

                  } else {      

                         top --;

                   for ( int j = mid +1; j < string .length()-1; j ++)

                         if ( string .charAt( j )!= charOne [ top --])

                               return "NO2" ;

                  }

                   return "YES" ;

            } else

                   for ( int k = mid +1; k < string .length()-1; k ++)

                         if ( string .charAt( k )!= charOne [ top --])

                         return "NO3" ;

             if ( top ==0)

             return "YES" ;

             return "Error" ;

      }

       public static void main(String[] args ) {

            Scanner scanner = new Scanner(System. in );

            System. out .println( "请输入待判断的字符串：" );

            String string = scanner .nextLine();

            HuiWenString huiWenString = new HuiWenString();

            System. out .println( huiWenString .isHuiWen( string ));

            

      }

}