solutions to code interviews

anagram.js

// helper function that builds the
// object to store the data
const buildCharObject = str => {
  const charObj = {}
  for(let char of str.replace(/[^\w]/g).toLowerCase()) {
    // if the object has already a key value pair
    // equal to the value being looped over,
    // increase the value by 1, otherwise add
    // the letter being looped over as key and 1 as its value
    charObj[char] = charObj[char] + 1 || 1
  }
  return charObj
}

// main function
const anagram = (strA, strB) => {
  // build the object that holds strA data
  const aCharObject = buildCharObject(strA)
  // build the object that holds strB data
  const bCharObject = buildCharObject(strB)

  // compare number of keys in the two objects
  // (anagrams must have the same number of letters)
  if(Object.keys(aCharObject).length !== Object.keys(bCharObject).length) {
    return false
  }
  // if both objects have the same number of keys
  // we can be sure that at least both strings
  // have the same number of characters
  // Now we can compare the two objects to see if both
  // have the same letters in the same amount
  for(let char in aCharObject) {
    if(aCharObject[char] !== bCharObject[char]) {
      return false
    }
  }
  // if both the above checks succeed,
  // you have an anagram: return true
  return true
}

fibonacci.js

const fibonacci = num => {
  // store the Fibonacci sequence you're going
  // to generate inside an array and
  // initialize the array with the first two
  // numbers of the sequence
  const result = [0, 1]

  for(let i = 2; i <= num; i++) {
    // push the sum of the two numbers
    // preceding the position of i in the result array
    // at the end of the result array
    const prevNum1 = result[i - 1]
    const prevNum2 = result[i - 2]
    result.push(prevNum1 + prevNum2)
  }
  // return the last value in the result array
  return result[num]
}

const fibonacci = num => {
  // if num is either 0 or 1 return num
  if(num < 2) {
    return num
  }
  // recursion here
  return fibonacci(num - 1) + fibonacci(num - 2)
}

find-vowels.js

const findVowels = str => {
  let count = 0
  const vowels = ['a', 'e', 'i', 'o', 'u']
  for(let char of str.toLowerCase()) {
    if(vowels.includes(char)) {
      count++
    }
  }
  return count
}

const findVowels = str => {
  const matched = str.match(/[aeiou]/gi)
  return matched ? matches.length : 0
}

fizzbuzz.js

const fizzBuzz = num => {
  for(let i = 1; i <= num; i++) {
    // check if the number is a multiple of 3 and 5
    if(i % 3 === 0 && i % 5 === 0) {
      console.log('fizzbuzz')
    } // check if the number is a multiple of 3
      else if(i % 3 === 0) {
      console.log('fizz')
    } // check if the number is a multiple of 5
      else if(i % 5 === 0) {
      console.log('buzz')
    } else {
      console.log(i)
    }
  }
}

palindrome.js

const palindrome = str => {
  // turn the string to lowercase
  str = str.toLowerCase()
  // reverse input string and return the result of the
  // comparisong
  return str === str.split('').reverse().join('')
}