### Distinct

January 17, 2020

**Write a function**

function solution(A);

that, given an array A consisting of N integers, returns the number of distinct values in array A.

For example, given array A consisting of six elements such that:

A[0] = 2

A[1] = 1

A[2] = 1

A[3] = 2

A[4] = 3

A[5] = 1

the function should return 3, because there are 3 **distinct values** appearing in array A, namely 1, 2 and 3.

Write an efficient algorithm for the following assumptions:

• N is an integer within the range [0..100,000];

• each element of array A is an integer within the range [−1,000,000..1,000,000].

Use **Set()** to store **unique values**.

```
function solution(A) {
// write your code in JavaScript (Node.js 8.9.4)
const dataset = new Set()
for(let i=0; i<A.length; i++) dataset.add(A[i])
return dataset.size
}
```