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
}