#F0526. Problem C: Square
Problem C: Square
题目描述

Problem C: Square
Given a set of sticks of various lengths, is it possible to join them end-to-end to form a square?
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.
For each case, output a line containing "yes" if is is possible to form a square; otherwise output "no".
样例 1
输入
3 4 1 1 1 1 5 10 20 30 40 50 8 1 7 2 6 4 4 3 5
输出
yes no yes
题目来源:fps-zhblue-waterloo-020921.xml;FPS 共享题包,题包内第 3 题。保留原作者与原赛事署名。