多项式 Wannafly挑战赛22

后缀表达式 大整数(加法、乘法、gcd java)

 import java.math.BigInteger;
 import java.util.Scanner;

 class Work {
     String str;
     int _num,_sym;
     int []sym=new int[1000];
     BigInteger []num=new BigInteger[1000];
     int []w=new int[1000];

     Work() {
         BigInteger x,y;
         int wx,wy;
         Scanner in=new Scanner(System.in);
         str=in.nextLine();
         work();
         x=num[1];
         wx=w[1];
         str=in.nextLine();
         work();
         y=num[1];
         wy=w[1];

         if (wx>wy)
             System.out.println("1/0");
         else if (wx<wy)
             System.out.println("0/1");
         else
         {
             BigInteger z;
             z=x.gcd(y);
             x=x.divide(z);
             y=y.divide(z);
             System.out.print(x+"/"+y);
         }
         in.close();
     }

     void cal()
     {
         if (sym[_sym]==2)
         {
             if (w[_num-1]<w[_num])
             {
                 w[_num-1]=w[_num];
                 num[_num-1]=num[_num];
             }
             else if (w[_num-1]==w[_num])
                 num[_num-1]=num[_num-1].add(num[_num]);
         }
         else if (sym[_sym]==3)
         {
             w[_num-1]+=w[_num];
             num[_num-1]=num[_num-1].multiply(num[_num]);
         }
         _sym--;
         _num--;
     }

     void work()
     {
         int len,i;
         BigInteger z;
         len=str.length();
         z=BigInteger.valueOf(1);
         _num=0;
         _sym=0;
         sym[0]=0;

         for (i=0;i<len;i++)
         {
             if (str.charAt(i)=='x')
             {
                 num[++_num]=z;
                 w[_num]=1;
             }
             else
             {
                 switch(str.charAt(i))
                 {
                     case '+':
                         while (sym[_sym]>=2)
                             cal();
                         sym[++_sym]=2;
                         break;
                     case '*':
                         while (sym[_sym]>=3)
                             cal();
                         sym[++_sym]=3;
                         break;
                     case '(':
                         sym[++_sym]=1;
                         break;
                     case ')':
                         while (sym[_sym]!=1)
                             cal();
                         _sym--;
                         break;
                 }
             }
         }
         while (_sym>0)
             cal();
     }
 }

 public class Main {
     public static void main(String[] args) {
         Work work=new Work();
     }
 }