gistfile1.js

/*
Write a function

function solution(A);

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

Assume that:

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].
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.

Complexity:

expected worst-case time complexity is O(N*log(N));
expected worst-case space complexity is O(N) (not counting the storage required for input arguments).
*/

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    const hashMap = {}
    const filteredArray = A.filter(item => {
        if (!hashMap[item]) {
            hashMap[item] = true
            return true
        }
        return false
    })
    console.log(filteredArray)
    return filteredArray.length
}