Skip to content# Running sum of 1d array code challenge

### Problem

### Solution

## Newsletter

— 1 min read

My approach to solving LeetCode’s Running sum of 1d array code challenge.

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`

.

We start by creating a new temporary array (`temp`

) and populating it with the first array's element (`nums[0]`

). We need to do this, as below we start for loop, where during each iteration, we will be using the last temporary array value (`temp[i - 1]`

) and sum it with the current's loop value (`nums[i]`

). We will push the result of this addition to the `temp`

array.

Finally, we return the `temp`

array.

```
1var runningSum = function (nums) {2 let temp = [nums[0]];3
4 for (let i = 1; i < nums.length; i++) {5 temp.push(temp[i - 1] + nums[i]);6 }7
8 return temp;9};
```

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