题解 | #构建乘积数组#

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# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
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# @param A int整型一维数组 
# @return int整型一维数组
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class Solution:
    def multiply(self , A: List[int]) -> List[int]:
        # 左右相乘 
        #    a0 a1 a2 a3 
        # b0 1  (a1 a2 a3)
        # b1 a0 1  (a2 a3)
        # b2 (a0 a1) 1  a3
        # b3 (a0 a1 a2) 1 
        length = len(A)
        B = [1 for i in range(length)]
        temp = 1
        for i in range(length):
            B[i] *= temp
            temp *= A[i]
        temp = 1
        for j in range(length-1,-1,-1):
            B[j] *= temp
            temp *= A[j]
        return B