Finding a ‘Lucky Integer’

Given an array, find the greatest value who’s numbers frequency is the same number as itself.

Example:

Input: [1,1,2,2,3,3]

Output: 2

It’s important to divide and conquere when working on algorithmic codes. This problem requires 3 steps.

1. Create a frequency table
2. Sort array in decending order
3. Iterate over the array until a hash key equals its value.

var findLucky = function(arr) {
    let hash = {}…