The prefix array is quite famous in the programming world. This article would discuss a variation of this scheme. This deals with the cumulative list product till a False value, and again starts cumulation of product from occurrence of True value. Let’s discuss certain way in which this can be performed.
Method #1 : Using Naive Method
In the naive method, we just construct the new list comprising of the the product of prev. value of list until False and restarts the procedure once a True value is encountered.
# Python3 code to demonstrate # Multiplication till Null value # using naive method # initializing list of lists test_list = [ 1 , 3 , 4 , False , 4 , 5 , False , 7 , 8 ] # printing original list print ( "The original list is : " + str (test_list)) # Multiplication till Null value # using naive method for i in range ( 1 , len (test_list)): if test_list[i]: test_list[i] * = test_list[i - 1 ] else : test_list[i] = 1 # printing result print ( "The computed modified new list : " + str (test_list)) |
The original list is : [1, 3, 4, False, 4, 5, False, 7, 8] The computed modified new list : [1, 3, 12, 1, 4, 20, 1, 7, 56]
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