# Sum of Two Numbers - Online Version

Implement a data structure with the following methods:

`add(int val)`

adds the value`val`

to the data structure`find(int val)`

returns whether there are two elements whose sum equals to`val`

**Constraints**

`n ≤ 10,000`

where`n`

is the number of times`add`

will be called`m ≤ 1,000`

where`m`

is the number of times`find`

will be called

https://binarysearch.com/problems/Sum-of-Two-Numbers-Online-Version

## Examples

### Example 1

**Input**

- methods =
`['constructor', 'add', 'find', 'add', 'find']`

- arguments =
`[[], [5], [10], [6], [11]]`

**Output**

- answer =
`[None, None, False, None, True]`

**Explanation**

- We create a
`TwoSum`

first - Then we add the number
`5`

to the data structure - We check if there’s two numbers whose sum is
`10`

. There isn’t, so we return`false`

- Then we add the number
`6`

to the data structure - We check if there’s two numbers whose sum is
`11`

, which there is since`5 + 6 = 11`

.

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