# Index with Equal Left and Right Sums

Given a list of integer `nums`

, return the earliest index `i`

such that the sum of the numbers left of `i`

is equal to the sum of numbers right of `i`

. If there’s no solution, return `-1`

.

Sum of an empty list is defined to be `0`

.

**Constraints**

`1 ≤ n ≤ 100,000`

where`n`

is the length of`nums`

https://binarysearch.com/problems/Index-with-Equal-Left-and-Right-Sums

## Examples

### Example 1

**Input**

- nums =
`[2, 3, 4, 0, 5, 2, 2]`

**Output**

- answer =
`3`

**Explanation**

Sum of the numbers left of index `3`

is `9`

and sum of the numbers right of index `3`

also `9`

.

### Example 2

**Input**

- nums =
`[1, -2, 2]`

**Output**

- answer =
`0`

**Explanation**

Sum of the numbers left of index `0`

is `0`

and sum of the numbers right of index `0`

also `0`

.

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