2574. Left and Right Sum Differences

Easy
Given a 0-indexed integer array nums, find a 0-indexed integer array answer where:
  • answer.length == nums.length.
  • answer[i] = |leftSum[i] - rightSum[i]|.
Where:
  • leftSum[i] is the sum of elements to the left of the index i in the array nums. If there is no such element, leftSum[i] = 0.
  • rightSum[i] is the sum of elements to the right of the index i in the array nums. If there is no such element, rightSum[i] = 0.
Return the array answer.
Example 1:
Input: nums = [10,4,8,3]
Output: [15,1,11,22]
Explanation: The array leftSum is [0,10,14,22] and the array rightSum is [15,11,3,0].
The array answer is [|0 - 15|,|10 - 11|,|14 - 3|,|22 - 0|] = [15,1,11,22].
Example 2:
Input: nums = [1]
Output: [0]
Explanation: The array leftSum is [0] and the array rightSum is [0].
The array answer is [|0 - 0|] = [0].
Constraints:
  • 1 <= nums.length <= 1000
  • 1 <= nums[i] <= 10^5

解題

func leftRigthDifference(nums []int) []int {
arr := make([]int, len(nums))
​
sum := 0
for i:=0; i<len(nums); i++ {
arr[i] = sum
sum += nums[i]
}
​
sum = 0
for i:=len(nums) - 1; i>=0; i-- {
arr[i] -= sum
arr[i] = abs(arr[i])
sum += nums[i]
}
​
return arr
}
​
func abs(a int) int {
if a < 0 { return -a }
return a
}