Frequency Calculator #JavaScript

frequency-calculator.js

// O(n)
// two loops is better than nested loops

function same(arr1, arr2) {
  if (arr1.length !== arr2.length) {
      return false
  }
  let frequencyCounter1 = {}
  let frequencyCounter2 = {}

  for (let val of arr1) { // of = value
      frequencyCounter1[val] = (frequencyCounter1[val] || 0) + 1
  }
  for (let val of arr2) {
      frequencyCounter2[val] = (frequencyCounter2[val] || 0) + 1
  }
  console.log({frequencyCounter1, frequencyCounter2})
  for (let key in frequencyCounter1) { // in = key

      // do the keys match?
      if (!(key ** 2 in frequencyCounter2)) {
          return false
      }
      // does the value count match?
      if (frequencyCounter2[key ** 2] !== frequencyCounter1[key]) {
          return false
      }
  }
  
  return true
    
}

same([1,2,2,3, 5], [9,1,4,4, 11])