2574. Left and Right Sum Differences

Problem Link

Description

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You are given a 0-indexed integer array nums of size n.

Define two arrays leftSum and rightSum 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 an integer array answer of size n where answer[i] = |leftSum[i] - rightSum[i]|.

 

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] <= 105

Solution

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Python3

class Solution:
    def leftRigthDifference(self, nums: List[int]) -> List[int]:
        left = 0
        right = sum(nums)
        res = []
        
        for x in nums:            
            right -= x
            
            res.append(abs(left - right))
            
            left += x
            
        return res