Doubles water！！！！！！只会水题怎么破

Doubles

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3927    Accepted Submission(s):
2732

Problem Description

As part of an arithmetic competency program, your
students will be given randomly generated lists of from 2 to 15 unique positive
integers and asked to determine how many items in each list are twice some other
item in the same list. You will need a program to help you with the grading.
This program should be able to scan the lists and output the correct answer for
each one. For example, given the list
1 4 3 2 9 7 18 22

your program
should answer 3, as 2 is twice 1, 4 is twice 2, and 18 is twice 9.

 

Input

The input file will consist of one or more lists of
numbers. There will be one list of numbers per line. Each list will contain from
2 to 15 unique positive integers. No integer will be larger than 99. Each line
will be terminated with the integer 0, which is not considered part of the list.
A line with the single number -1 will mark the end of the file. The example
input below shows 3 separate lists. Some lists may not contain any
doubles.

 

Output

The output will consist of one line per input list,
containing a count of the items that are double some other item.

 

Sample Input

1 4 3 2 9 7 18 22 0

2 4 8 10 0

7 5 11 13 1 3 0

-1

 

Sample Output

3

2

0

 #include <iostream>
 #include <cstdio>
 using namespace std;
 int main()
 {
     int n;
     int a[];
     //freopen("in.txt","r",stdin);
     while(cin>>n&&n!=-)
     {
         int count=,i=,j=,sum=;
         a[]=n;
         while(cin>>a[count++]&&a[count-]!=);
         count-=;
         for(i=;i<count;i++)
         {
             for(j=;j<count;j++)
             {
                 if(a[i]==*a[j])
                     sum++;
             }
         }
         cout<<sum<<endl;
     }
 }