Worst case: (10,000)^2 = 100,000,000

Assuming 2 billion actions per second (easily achieveable on intel core i5), the worst case is 500 ms

Indeed, this code runs in 571 ms

```
class Solution {
//Find partial sum between start inclusive and stop exclusive
public int sum(int[] nums, int start, int stop){
int ret = 0;
for(int i = start; i < stop; i++){
ret += nums[i];
}
return ret;
}
public int pivotIndex(int[] nums) {
//Iterate through array positions: O(n^2)
for(int i = 0; i < nums.length; i++){
if(sum(nums, 0, i) == sum(nums, i + 1, nums.length)){
return i;
}
}
//If not found, return -1
return -1;
}
}
```