238.product_of_array_except_self

Author: Deftly

README.md

@@ -9,6 +9,7 @@
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leetcode/0238.product_of_array_except_self/238.product_of_array_except_self.go

@@ -0,0 +1,19 @@
+package data_structures_algorithms
+
+func productExceptSelf(nums []int) []int {
+	length := len(nums)
+	result := make([]int, length)
+	result[0], result[length-1] = 1, 1
+
+	for i := 1; i < length; i++ {
+		result[i] = result[i-1] * nums[i-1]
+	}
+
+	postProduct := 1
+	for i := length - 2; i >= 0; i-- {
+		postProduct *= nums[i+1]
+		result[i] *= postProduct
+	}
+
+	return result
+}

leetcode/0238.product_of_array_except_self/README.md

@@ -0,0 +1,27 @@
+# 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:
+```shell 
+Input: nums = [1,2,3,4]
+Output: [24,12,8,6]
+```
+
+#### Example 2:
+```shell 
+Input: nums = [-1,1,0,-3,3]
+Output: [0,0,9,0,0]
+```
+
+<br>
+
+#### Constraints:
+- <code>2 <= nums.length <= 10<sup>5</sup></code>
+- `-30 <= nums[i] <= 30`
+- The product of any prefix or suffix of `nums` is guaranteed to fit in a 32-bit integer.
+
+**Follow up**: Can you solve the problem using only `O(1)` space? The output array does no tcount as extra space for space complexity analysis