Balanced Bitstring(字符串+思维) Codeforces Round #668 (Div. 2)
原题链接:https://codeforces.com/contest/1405/problems测试样例input964100110321?1321?044???741?0??1?101011??11??11421??144?0?062???00outputYESYESNOYESYESNONOYESNONoteForthefirsttestcase,thestringisalreadya4-ba