Running Sum of 1d Array

Problem Description

Given an array nums. We define a running sum of an array as runningSum[i] = sum(nums[0]…nums[i]). Return the running sum of nums.

Key Insights

• The running sum at index i is the sum of all elements from the start of the array up to index i.
• This can be achieved using a single pass through the array, maintaining a cumulative sum.
• The solution has linear time complexity, making it efficient for the input size constraints.

Space and Time Complexity

Time Complexity: O(n)
Space Complexity: O(n) (for the output array)

Solution

To solve the problem, we can use an iterative approach where we maintain a cumulative sum as we traverse the input array. We'll create a new array to store the running sums. For each element in the input array, we add the current element to the cumulative sum and store it in the corresponding index of the new array.

Code Solutions