how many items in each list are twice

【文件属性】：
文件名称：how many items in each list are twice
文件大小：577B
文件格式：TXT
更新时间：2013-05-23 10:24:46
Doubles,acm 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.