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# 2270. Number of Ways to Split Array

🟧 Medium

You are given a **0-indexed** integer array `nums` of length `n`.

`nums` contains a **valid split** at index `i` if the following are true:

* The sum of the first `i + 1` elements is **greater than or equal to** the sum of the last `n - i - 1` elements.
* There is **at least one** element to the right of `i`. That is, `0 <= i < n - 1.`

Return *the number of **valid splits** in `nums.`*

## Example 1

> **Input**: nums = \[10,4,-8,7]\
> **Output**: 2\
> **Explanation**: There are three ways of splitting nums into two non-empty parts:\
> Split nums at index 0. Then, the first part is \[10], and its sum is 10. The second part is \[4,-8,7], and its sum is 3. Since 10 >= 3, i = 0 is a valid split.\
> Split nums at index 1. Then, the first part is \[10,4], and its sum is 14. The second part is \[-8,7], and its sum is -1. Since 14 >= -1, i = 1 is a valid split.\
> Split nums at index 2. Then, the first part is \[10,4,-8], and its sum is 6. The second part is \[7], and its sum is 7. Since 6 < 7, i = 2 is not a valid split.\
> Thus, the number of valid splits in nums is 2.

## Example 2

> **Input**: nums = \[2,3,1,0]\
> **Output**: 2\
> **Explanation**: There are two valid splits in nums:\
> Split nums at index 1. Then, the first part is \[2,3], and its sum is 5. The second part is \[1,0], and its sum is 1. Since 5 >= 1, i = 1 is a valid split.\
> Split nums at index 2. Then, the first part is \[2,3,1], and its sum is 6. The second part is \[0], and its sum is 0. Since 6 >= 0, i = 2 is a valid split.

## Constraints

* `2 <= nums.length <= 10^5`
* `-10^5 <= nums[i] <= 10^5`

## Solution

My Solution

```go
func waysToSplitArray(nums []int) int {
    sum := 0
    for _, num := range nums {
        sum += num
    }

    var (
        count   = 0
        leftSum = 0
    )
    for i := 0; i < len(nums)-1; i++ {
        leftSum += nums[i]
        if leftSum >= (sum - leftSum) {
            count++
        }
    }

    return count
}
```

![result](https://600345290-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FrSK2xH3txU3tYyDsT8mQ%2Fuploads%2Fgit-blob-56314a7105c8e860637897e0a42e3cc337352696%2F2270.png?alt=media)

Leetcode: [link](https://leetcode.com/problems/number-of-ways-to-split-array/description/)