Implement it on LeetCode. This should take just a few lines. Watch for the edge case: what if the array has only one element? The running sum is just that element. This prefix pattern appears everywhere. Once you see "cumulative" or "sum of all previous," you know to carry forward a running total.
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
$ curl repovive.com/roadmaps/maang-interview-prep/arrays-hashing/running-sum-implementation
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