Running Sum of an Array
Easy
The Running Sum of an Array problem involves calculating the cumulative sum of elements in an array.
Given an integer array arr[] of size n, return an array where each element at index i represents the sum of all elements from index 0 to i.
The running sum at index i is calculated as:
runningSum[i] = arr[0] + arr[1] + ... + arr[i]
This problem helps in understanding Prefix Sum, cumulative computations, and efficient array traversal.
Example 1
Input
arr[] = [1,2,3,4]
Output
[1,3,6,10]
Explanation
The running sum is calculated as: 1 1 + 2 = 3 1 + 2 + 3 = 6 1 + 2 + 3 + 4 = 10 Hence, the resulting array is [1,3,6,10].
Example 2
Input
arr[] = [5,1,2,7]
Output
[5,6,8,15]
Explanation
Each element in the output array stores the cumulative sum of all elements up to that index.
Constraints
1 <= n <= 10^5
-10^9 <= arr[i] <= 10^9
Hints:
Hint 1
Maintain a variable to store the cumulative sum while traversing the array. Add the current element to it and store the updated sum in the result array.
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Input
Expected Output