productofarrayexceptself.py

# #time and space complexity is O(n*n)
# def productexceptself(nums):
#     result = []

#     for index, _num in enumerate(nums):
#         lhs = []
#         rhs = []
#         if index > 0: #This checks whether there are any elements before the current index.If index == 0, there are no elements before it, so lhs should stay empty.
#             lhs = nums[0:index] #element before the index
#         if index < len(nums) - 1:
#             rhs = nums[index + 1:] #This checks whether there are any elements after the current index. If index == len(nums) - 1, that means we are at the last element, so there's nothing after it.
#         lhs.extend(rhs)
#         # print(lhs)
#         res = 1
#         for n in lhs: #This condition is because we want product of all elements in the list
#            res *= n
#         result.append(res)
#     return result

# nums = [1,2,4,6]
# print(productexceptself(nums))

#time complexity O(n)
#space complexity O(1)

# def product_exceptself(nums: list):
#     res = [1] * len(nums)
#     prefix = 1

#     for i in range(len(nums)):
#         res[i] = prefix
#         prefix *= nums[i]

#     postfix = 1
#     for i in range(len(nums)-1, -1, -1):
#         res[i] = postfix * res[i]
#         postfix *= nums[i]

#     return res

# nums = [1,2,4,6]
# print(product_exceptself(nums))