def lcs(X, Y): # 创建一个二维数组 m = len(X) n = len(Y) L = [[None]*(n+1) for i in range(m+1)] # 填充L [i] [0] = 0 和 L [0] [j] = 0 for i in range(m+1): for j in range(n+1): if i == 0 or j == 0: L[i][j] = 0 # 填充L [i] [j]，如果X [i-1] == Y [j-1]，则L [i] [j] = L [i-1] [j-1] +1，否则L [i] [j] = max（L [i-1] [j]，L [i] [j-1]） for i in range(1, m+1): for j in range(1, n+1): if X[i-1] == Y[j-1]: L[i][j] = L[i-1][j-1] + 1 else: L[i][j] = max(L[i-1][j], L[i][j-1]) # L [m] [n]存储LCS的长度值 return L[m][n代码运行不出来

抱歉，可能是因为代码中存在一些格式错误导致不能正常运行。以下是修改后的代码：

def lcs(X, Y):
    # 创建一个二维数组
    m = len(X)
    n = len(Y)
    L = [[None]*(n+1) for i in range(m+1)]
 
    # 填充L [i] [0] = 0 和 L [0] [j] = 0
    for i in range(m+1):
        for j in range(n+1):
            if i == 0 or j == 0:
                L[i][j] = 0
 
    # 填充L [i] [j]，如果X [i-1] == Y [j-1]，则L [i] [j] = L [i-1] [j-1] +1，否则L [i] [j] = max（L [i-1] [j]，L [i] [j-1]）
    for i in range(1, m+1):
        for j in range(1, n+1):
            if X[i-1] == Y[j-1]:
                L[i][j] = L[i-1][j-1] + 1
            else:
                L[i][j] = max(L[i-1][j], L[i][j-1])
 
    # L [m] [n]存储LCS的长度值
    return L[m][n]

X = "AGGTAB"
Y = "GXTXAYB"
print("Length of LCS is ", lcs(X, Y))

这段代码可以计算出 X 和 Y 的最长公共子序列的长度，输出结果为 4。