使用KMP算法能减少完成的串模式匹配的回溯，因此该算法每当一趟匹配过程中出现字符比较不等时，不需要回溯i指针，而是利用已匹配到的“部分匹配”的结果将模式右滑尽可能远的一段距离进行比较-KMP algorithm can reduce the use of string pattern matching complete retrospective, so the algorithm whenever the character appears in a visit the matching process more unequal, i do not need to back a pointer, but the use has been matched to a " partial match"　results will be right-slip model as far a distance to compare