Product of Array Except Self
Given an integer array nums, return an array answer where answer[i] is the product of every element except nums[i].
You must write it without using division, and it should run in O(n).
Example 1
answer[0] = 2*3*4 = 24, answer[1] = 1*3*4 = 12, and so on.
Example 2
Think about what sits to the left of each index and what sits to the right, and how two passes can give you both.
Examples
Example 1
- Input:
- [1,2,3,4]
- Output:
- [24,12,8,6]
answer[0] = 2*3*4 = 24, answer[1] = 1*3*4 = 12, answer[2] = 1*2*4 = 8, answer[3] = 1*2*3 = 6.
Example 2
- Input:
- [-1,1,0,-3,3]
- Output:
- [0,0,9,0,0]
Every position except the zero itself includes the zero in its product. At the zero, the product of the others is -1*1*-3*3 = 9.
Example 3
- Input:
- [0,0]
- Output:
- [0,0]
With two zeros, every answer is zero.
Constraints
2 <= nums.length <= 10^5-30 <= nums[i] <= 30- The product of any prefix or suffix fits in a 32-bit integer.
- Division is not allowed.
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