2019-08-16 剑指 构建乘积数组

class Solution:
    def multiply(self, A:List):
        B=[]
        for i in range(len(A)):
            tmp = 1
            for i,n in enumerate(A):
               if  i!=len(B):tmp*=n
            B.append(tmp)
        return B

对连乘降低复杂度，10min

class Solution:
    def multiply(self, A:List):
        B=[]
        a=[1 for i in range(len(A))]
        b=[1 for i in range(len(A))]

        for i in range(1,len(A)):
            a[i]=a[i-1]*A[i-1]
            b[len(A) - 1 - i] = b[len(A) - 1 - i + 1] * A[len(A) - 1 - i+1]
        for i in range(len(A)):
            B.append(a[i]*b[i])
        return B