自行设计随机生成n=30的S串；实现删除子串算法Deletestr（sqstr s，sqstr sub）；分析T（n）；讨论s=’aaa….abbb….b’，sub=’ab’的执行结果。-Design their own randomly generated n = 30 S-string　Delete the substring the algorithm Deletestr (sqstr s, sqstr sub)　analysis of T (n)　discussion s =　 aaa .... abbb .... b　, sub =　 ab　 the The results of the implementation.