Codeforces #36 A Extra-terrestrial Intelligence
Extra-terrestrial Intelligence
ファイル入出力だとデバッグが地味に面倒。
input = open("input.txt","r") output = open("output.txt","w") input.readline() if len(set(input.readline().split("1")[1:-1])) <= 1: output.write("YES") else: output.write("NO")