华为2014第三题

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.*;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.security.auth.kerberos.KerberosKey;
public class Main{
int N=8;
int [] step=new int
;
String ope[]={"+","-",""};
ScriptEngineManager manager=new ScriptEngineManager();
ScriptEngine engine=manager.getEngineByName("js");
private void step()
{
step[N-1]++;
for(int i=N-1;i>=0;i--)
{
if(step[i]>2)
{
step[i]=step[i]%3;
if(i!=0)
step[i-1]++;
}
else {
break;
}
}
}
public int search() throws ScriptException
{
int K=(int)Math.pow(3, N);
int count=0;
for(int i=0;i<K;i++)
{
String operation="1"+ope[step[0]]+"2"+ope[step[1]]+"3"+ope[step[2]]+
"4"+ope[step[3]]+"5"+ope[step[4]]+"6"+ope[step[5]]+
"7"+ope[step[6]]+"8"+ope[step[7]]+"9";
//Object result=engine.eval(operation);
//double d=((Double)result).doubleValue();
String result=sizeyunsuan(operation);
double d=Double.parseDouble(result);
if((int)d==5)
{
count++;
}
step();
}
return count;
}
private static String addBigDecimal(String a,String b)
{
double a1=Double.parseDouble(a);
double b1=Double.parseDouble(b);
BigDecimal a2=BigDecimal.valueOf(a1);
BigDecimal b2=BigDecimal.valueOf(b1);
BigDecimal s=a2.add(b2);
return s.toString();
}
private static String substractBigDecimal(String a,String b)
{
double a1=Double.parseDouble(a);
double b1=Double.parseDouble(b);
BigDecimal a2=BigDecimal.valueOf(a1);
BigDecimal b2=BigDecimal.valueOf(b1);
BigDecimal s=a2.subtract(b2);
return s.toString();
}
private static String sizeyunsuan(String s)
{
//1、先将  +-*/找出来
int p=0;//the count of (+-*/)
for(int i=0;i<s.length();i++)
{
if(s.charAt(i)=='+' || s.charAt(i)=='-')
p++;
}
//将字符串按照运算符进行切割总共有  2*p+1个段   example:p=5
String[] piece=new String[2*p+1];// save pieces divided by operator   11 pieces
int start=0,index=0;//
for(int i=0;i<s.length();i++)
{
if(s.charAt(i)=='+' || s.charAt(i)=='-')
{
piece[index]=s.substring(start,i);//index=0  i=1  p[0]="9"
index++;
piece[index]=""+s.charAt(i);    //index=1  i=1  p[1]="+"
index++;
start=i+1;   //start=2
}
}
// last piece;
piece[index]=s.substring(start,s.length());
///
int count=p;
while(count>0)
{
//then calculate +-
for(int i=0;i<piece.length;i++)
{
if(piece[i].equals("+") || piece[i].equals("-"))
{
//find strs in piece has not calculated
//find strs left not equals "p"
int l=0;
for(l=i-1;l>-1;l--)
{
if(!piece[l].equals("p"))
break;
}
//find strs right not equals "p"
int r=0;
for(r=i+1;r<piece.length;r++)
{
if(!piece[r].equals("p"))
break;
}
if(piece[i].equals("+"))
{
piece[i]=addBigDecimal(piece[l], piece[r]);
piece[l]="p";
piece[r]="p";
count--;
}
else
{
piece[i]=substractBigDecimal(piece[l], piece[r]);
piece[l]="p";
piece[r]="p";
count--;
}
//break;
}
}
}
String r="";
//find the string not equals "p"
for(int i=0;i<piece.length;i++)
{
if(!piece[i].equals("p"))
{
r=piece[i];
break;
}
}
return r;
}
public static void main(String[] args) throws ScriptException{
Main main=new Main();
long begin=System.currentTimeMillis();
int c=main.search();
long end=System.currentTimeMillis();
System.out.println(c);
System.out.println("共花费"+(end-begin)+"ms");
}

}