Square
Time Limit : 10000/5000ms (Java/Other) Memory Limit : 65536/32768K (Java/Other)
Total Submission(s) : 448 Accepted Submission(s) : 134
Problem Description
Given a set of sticks of various lengths, is it possible to join them end-to-end to form a square?<br>
Input
The first line of input contains N, the number of test cases. Each test case begins with an integer 4 <= M <= 20, the number of sticks. M integers follow; each gives the length of a stick - an integer between 1 and 10,000.<br>
Output
For each case, output a line containing "yes" if is is possible to form a square; otherwise output "no".<br>
Sample Input
3<br>4 1 1 1 1<br>5 10 20 30 40 50<br>8 1 7 2 6 4 4 3 5<br>
Sample Output
yes<br>no<br>yes<br>
Source
University of Waterloo Local Contest 2002.09.21