238. Product of Array Except Self
Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i].
The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
You must write an algorithm that runs in O(n) time and without using the division operation.
Example 1:
Input: nums = [1,2,3,4] Output: [24,12,8,6]
Example 2:
Input: nums = [-1,1,0,-3,3] Output: [0,0,9,0,0]
Constraints:
2 <= nums.length <= 105-30 <= nums[i] <= 30- The product of any prefix or suffix of
numsis guaranteed to fit in a 32-bit integer.
Follow up: Can you solve the problem in O(1) extra space complexity? (The output array does not count as extra space for space complexity analysis.)
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Hints open one at a time
Hint 1
Think how you can efficiently utilize prefix and suffix products to calculate the product of all elements except self for each index. Can you pre-compute the prefix and suffix products in linear time to avoid redundant calculations?
Hint 2
Can you minimize additional space usage by reusing memory or modifying the input array to store intermediate results?
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1class Solution:
2 def productExceptSelf(self, nums: List[int]) -> List[int]:
3
Starter codePython 3Spaces: 4
Loading editor…
1class Solution:
2 def productExceptSelf(self, nums: List[int]) -> List[int]:
3
Starter codePython 3Spaces: 4
Examples
Input
[1,2,3,4]
Input
[-1,1,0,-3,3]
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