從一道簡單題談程序設計的思維
題目
Stick
Problem
Anthony has collected a large amount of sticks for manufacturing chopsticks. In order to simplify his job, he wants to fetch two equal-length sticks for machining at a time. After checking it over, Anthony finds that it is always possible that only one stick is left at last, because of the odd number of sticks and some other unknown reasons. For example, Anthony may have three sticks with length 1, 2, and 1 respectively. He fetches the first and the third for machinning, and leaves the second one at last. Your task is to report the length of the last stick.
Input
The input file will consist of several cases.
Each case will be presented by an integer n (1 <= n <= 100, and n is odd) at first. Following that, n positive integers will be given, one in a line. These numbers indicate the length of the sticks collected by Anthony.
The input is ended by n = 0.
Output
For each case, output an integer in a line, which is the length of the last stick.
Sample Output
2
讀者可先行思考，詳細的分析以后再給出。
參考資料
郭嵩山、張子臻、王磊、湯振東著 國際大學生程序設計競賽例題解（五） 電子工業(yè)出版社