3. Cumulative Steps
A pedometer app logs how many steps a user took during each hour of the day. The user wants a running tally instead: for every hour, the total number of steps taken from the first hour up to and including that hour.
Write a method runningSum that takes the array nums of hourly step counts and returns an array of the same length whose element i is the sum of nums[0] through nums[i].
Example 1
- Input:
- nums = [1,2,3,4]
- Output:
- [1,3,6,10]
- Explanation:
The totals after each hour are 1, 1+2=3, 1+2+3=6 and 1+2+3+4=10.
Example 2
- Input:
- nums = [500,0,250]
- Output:
- [500,500,750]
- Explanation:
An hour with no steps leaves the running total unchanged: 500, 500, 750.
Constraints
1 ≤ nums.length ≤ 1000
0 ≤ nums[i] ≤ 105
How this problem is judged
- Answers
- Your answer must match exactly. Numbers compare by value, so 2 and 2.0 are equal.
Expected complexity
- Time
- O(n)
- Space
- O(n)