记录编号	2409	评测结果	WAAAAWAAAA
题目名称	算24点	最终得分	80
用户昵称	zqzas	是否通过	未通过
代码语言	C	运行时间	0.010 s
提交时间	2008-09-20 14:31:58	内存使用	1.52 MiB

#include<stdio.h>
#include<stdlib.h>

int num[4],taken[4],record[5][3];
FILE *ifp,*ofp;

void ini(void);
void next(long sum,long k);
void swap(int *a,int *b);

int main(void)
{
  long i;

  ini();
  for(i=0;i<4;++i)
    {
      taken[i]=1;
      next(num[i],2);
      taken[i]=0;
    }
  fprintf(ofp,"No answer!");
  fclose(ifp);
  fclose(ofp);
  return 0;
}
void ini(void)
{
  ifp=fopen("point24.in","r");
  ofp=fopen("point24.out","w");
  fscanf(ifp,"%ld%ld%ld%ld",&num[0],&num[1],&num[2],&num[3]);
}
void next(long sum,long k)
{
  long i,j;

  if(k==5)
    {
      if(sum==24)
	{
	  for(i=2;i<5;++i)
	    {
	      if(record[i][0]<record[i][1] 
		 && record[i][2]!=1 && record[i][2]!=3)
		swap(&record[i][0],&record[i][1]);
	      fprintf(ofp," %ld",record[i][0]);
	      switch (record[i][2])
		{
		case 0:
		  fprintf(ofp,"+%ld=%ld",record[i][1],
			  record[i][0]+record[i][1]);
		  break;
		case 1:
		  fprintf(ofp,"-%ld=%ld",record[i][1],
			  record[i][0]-record[i][1]);
		  break;
		case 2:
		  fprintf(ofp,"*%ld=%ld",record[i][1],
			  record[i][0]*record[i][1]);
		  break;
		case 3:
		  fprintf(ofp,"/%ld=%ld",record[i][1],
			  record[i][0]/record[i][1]);
		}
	      if(i!=4)
		fputc('\n',ofp);
	    }
	  fclose(ifp);
	  fclose(ofp);
	  exit(0);
	}
      return;
    }
  for(i=0;i<4;++i)
    if(!taken[i])
      {
	taken[i]=1;
	record[k][0]=sum;
	record[k][1]=num[i];
	for(j=0;j<4;++j)
	  {
	    record[k][2]=j;
	    switch(j)
	      {
	      case 0:
		next(record[k][0]+record[k][1],k+1);
		break;
	      case 1:
		if(record[k][0]-record[k][1]>0)
		  next(record[k][0]-record[k][1],k+1);
		swap(&record[k][0],&record[k][1]);
		if(record[k][0]-record[k][1]>0)
		  next(record[k][0]-record[k][1],k+1);
		break;
	      case 2:
		next(record[k][0]*record[k][1],k+1);
		break;
	      case 3:
		if(record[k][1]!=0 && record[k][0]%record[k][1]==0)
		  next(record[k][0]/record[k][1],k+1);
		swap(&record[k][0],&record[k][1]);
		if(record[k][1]!=0 && record[k][0]%record[k][1]==0)
		  next(record[k][0]/record[k][1],k+1);
		break;
	      }
	    record[k][2]=0;
	  }
	taken[i]=0;
	record[k][0]=record[k][1]=0;
      }
}
void swap(int *a,int *b)
{
  int c;

  c=(*a);
  (*a)=(*b);
  (*b)=c;
}