最长公共子序列（Python）

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参考：手写代码必备手册

__author__ = 'Administrator'def lcs(x,y):    d = [0] * (len(x) + 1)    for i in range(0,len(d)):        d[i] = [0] * (len(y) + 1)    for i in range(1,len(x) + 1):        for j in range(1, len(y) + 1):            if x[i-1] == y[j-1]:                d[i][j] = d[i-1][j-1] + 1            else:                d[i][j] = max(d[i-1][j],d[i][j-1])    print ddef lcs_extend(x,y):    d = [0] * (len(x) + 1)    p = [0] * (len(x) + 1)    for i in range(0,len(d)):        d[i] = [0] * (len(y) + 1)        p[i] = [0] * (len(y) + 1)    for i in range(1,len(x) + 1):        for j in range(1, len(y) + 1):            if x[i-1] == y[j-1]:                d[i][j] = d[i-1][j-1] + 1                p[i][j] = 1            elif d[i-1][j] > d[i][j-1]:                d[i][j] = d[i-1][j]                p[i][j] = 2            else:                d[i][j] = d[i][j-1]                p[i][j] = 3    print d    print p    lcs_print(x,y,len(x),len(y),p)def lcs_print(x,y,lenX,lenY,p):    if lenX == 0 or lenY == 0:        return    if p[lenX][lenY] == 1:        lcs_print(x,y,lenX-1,lenY-1,p)        print x[lenX-1],    elif p[lenX][lenY] == 2:        lcs_print(x,y,lenX-1,lenY,p)    else:        lcs_print(x,y,lenX,lenY-1,p)x = 'abcdf'y = 'facefff'lcs_extend(x,y)

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