用kmp算法病毒感染检测

以下是使用KMP算法进行病毒感染检测的示例：

def KMPSearch(pat, txt):
    M = len(pat)
    N = len(txt)
 
    lps = [0]*M
    j = 0
 
    computeLPSArray(pat, M, lps)
 
    i = 0
    while i < N:
        if pat[j] == txt[i]:
            i += 1
            j += 1
 
        if j == M:
            print("病毒感染检测: 病毒模式在索引 " + str(i-j) + " 处被找到")
            j = lps[j-1]
 
        elif i < N and pat[j] != txt[i]:
            if j != 0:
                j = lps[j-1]
            else:
                i += 1
 
def computeLPSArray(pat, M, lps):
    len = 0
    lps[0]
    i = 1
 
    while i < M:
        if pat[i] == pat[len]:
            len += 1
            lps[i] = len
            i += 1
        else:
            if len != 0:
                len = lps[len-1]
            else:
                lps[i] = 0
                i += 1

txt = "ABABDABACDABABCABAB"
pat = "ABABCABAB"
KMPSearch(pat, txt)