Codeforces Round #358 (Div. 2) B. Alyona and Mex 水题
B.AlyonaandMex题目连接:http://www.codeforces.com/contest/682/problem/BDescriptionSomeonegaveAlyonaanarraycontainingnpositiveintegersa1, a2, ..., an.Inoneoperation,Alyonacanchooseanyelementofthearrayanddec