Doubles

Time Limit: 1000MS Memory Limit: 10000K
Total Submissions: 16876 Accepted: 9666

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 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
解:
这道题很水,仅仅需要用两层循环来枚举所有的数据对就可以了。不过这里有个数组分配的问题,题目中说到2-15个两两不同,于是我给arr[]分配了15个,在浙江大学的ACM系统是AC的,但是在北京大学的ACM系统是Runtime Error,分配20个之后才AC。
#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
	int arr[20];
	cin>>arr[0];
	while (arr[0] != -1) {
		int i = 0, counter = 0;
		while (arr[i] != 0) {
			i++;
			cin>>arr[i];
		}
		for (int j = 0; j < i - 1; j++) {
			for (int k = j + 1; k < i; k++) {
				if ((arr[k] * 2 == arr[j]) || (arr[j] * 2 == arr[k])) {
					counter++;
				}
			}
		}
		cout<<counter<<endl;
		cin>>arr[0];
	}	
	return 0;
}
Result Memory Time Language Code Length
Accepted 248K 16MS C++ 445B

 

Tonitech版权所有 | 转载请注明出处: http://www.tonitech.com/1673.html

发表评论