Fundamentals problem solving-2

// Create a function in JavaScript that prints the numbers from 1 to n. For multiples of 3, print "Fizz" instead of the number. For multiples of 5, print "Buzz" instead of the number. For numbers which are multiples of both 3 and 5, print "FizzBuzz" instead of the number.(Leetcode-412)
// function fizzBuzz(n) {
//   const resultArr = []
//   for (let i = 1; i <= n; i++) {
//     if (i % 3 === 0 && i % 5 === 0) {
//       resultArr.push('FizzBuzz')
//     } else if (i % 3 === 0) {
//       resultArr.push('Fizz')
//     } else if (i % 5 === 0) {
//       resultArr.push('Buzz')
//     } else {
//       resultArr.push(i.toString())
//     }
//   }
//   return resultArr
// }

// fizzBuzz(3) // ['1', '2', 'Fizz']
// fizzBuzz(5)// ['1', '2', 'Fizz', 4, 'Buzz']
fizzBuzz(15) //["1","2","Fizz","4","Buzz","Fizz","7","8","Fizz","Buzz","11","Fizz","13","14","FizzBuzz"]

// Create a function in JavaScript that counts the number of vowels in a given string.
//O(n)
// const countVowels = (str) => {
//   const vowels = 'aeoiouAEOIU'
//   let count = 0
//   for (let char of str) {
//     if (vowels.includes(char)) {
//       count++
//     }
//   }

//   return count
// }
// console.log(countVowels('hello')) // Output: 2
// console.log(countVowels('world')) // Output: 1
// console.log(countVowels('aeiouAEIOU')) // Output: 10
// console.log(countVowels('bcdfghjklmnp')) // Output: 0
// console.log(countVowels('')) // Output: 0
// console.log(countVowels('xyz')) // Output: 0

//Leetcode-2586
//TIme and space complexity O(n)
// var vowelStrings = function (words, left, right) {
//   let count = 0
//   const vowels = 'aeiou'
//   for (let i = left; i <= right; i++) {
//     console.log(words[i][0], words[i][words[i].length - 1])
//     if (
//       vowels.includes(words[i][0]) &&
//       vowels.includes(words[i][words[i].length - 1])
//     ) {
//       count++
//     }
//   }

//   return count
// }

// console.log(vowelStrings(['are', 'amy', 'u'], 0, 2))

//Time complexity - O(n)
//space complexity - O(n)
// Leetcode-2129
// var capitalizeTitle = function (title) {
//  split the title into words and make it lowercase
//   const words = title.toLowerCase().split(' ')
//   const outputStrArr = []
//   for (let word of words) {
//     if (word.length > 2) {
//       outputStrArr.push(word[0].toUpperCase() + word.slice(1))
//     } else {
//       outputStrArr.push(word)
//     }
//   }

//   return outputStrArr.join(' ')
// }

// console.log(capitalizeTitle('capiTalIze tHe titLe'))
// console.log(capitalizeTitle('i lOve leetcode'))

// Create a function in JavaScript that checks whether a given number is a prime number.
// A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
// The function should return false for numbers less than 2.
// The function should efficiently check for divisors up to the square root of num.

//O(√n)
//space complexity O(1)
// function isPrime(n) {
//   if (n <= 1) return false //0, 1 are not prime numbers
//   if(n <= 3) return true  //2, 3 are prime numbers
//   for(let i = 2; i <= Math.sqrt(n); i++){
//     if(n % i === 0) return false
//     console.log(n % i)
//   }
//   return true
// }
//5, 7, 11, 13

//6k + 1 = 7
//6k - 1 = 5
//optimization
//time complexity O(√n).
//space complexity O(1)
// function isPrime(n) {
//   if (n <= 1) return false
//   if (n <= 3) return true
//   if (n % 2 === 0 || n % 3 === 0) return false

//   for (let i = 5 ; i <= Math.sqrt(n); i+= 6 ){
//     if(n % i === 0 || n % (i + 2) === 0) return false
//   }

//   return true
// }
// // Test cases
// console.log(isPrime(2)) // true
// console.log(isPrime(3)) // true
// console.log(isPrime(4)) // false
// console.log(isPrime(5)) // true
// console.log(isPrime(29)) // true
// console.log(isPrime(97)) // true
// console.log(isPrime(100)) // false

// Create a function in JavaScript that removes duplicate values from an array and returns a new array containing only unique values
// function removeDuplicates() {}
// console.log(removeDuplicates([1, 2, 2, 3, 4, 4])) // Output: [1, 2, 3, 4]
// console.log(removeDuplicates(['a', 'b', 'a', 'c', 'b'])) // Output: ['a', 'b', 'c']
// console.log(removeDuplicates([true, false, true, true])) // Output: [true, false]
// console.log(removeDuplicates([1, '1', 2, '2', 2])) // Output: [1, '1', 2, '2']
// console.log(removeDuplicates([])) // Output: []
// console.log(removeDuplicates([n ull, null, undefined, undefined])) // Output: [null, undefined]

//Leetcode-217
// var containsDuplicate = function (nums) {
//   const set = new Set()
//   for (num of nums) {
//     if (set.has(num)) {
//       return true
//     } else {
//       set.add(num)
//     }
//   }

//   return false
// }

// Write a function to reverse a string(Leetcode-344)
//Create a function in JavaScript that takes a string as input and returns a new string with the characters in reverse order.

// const reverseString = (str) => {}

//  Example of usage:
// console.log(reverseString("hello"));           // Output: "olleh"
// console.log(reverseString("world"));           // Output: "dlrow"
// console.log(reverseString("!dlroW ,olleH"));   // Output: "Hello, World!"
// console.log(reverseString(""));                // Output: ""
// console.log(reverseString("12345"));           // Output: "54321"
// console.log(reverseString("racecar"));         // Output: "racecar"

// Create a function in JavaScript that finds the intersection of two arrays, returning a new array containing elements that are present in both input arrays. (Leetcode-349)
var intersection = function (nums1, nums2) {
  const arr1Set = Array.from(new Set(nums1))
  const arr2Set = new Set(nums2)
  const resultArr = []
  for (num of arr1Set) {
    if (arr2Set.has(num)) {
      resultArr.push(num)
    }
  }

  return resultArr
}

console.log(intersection([1, 2, 2, 1], [2, 2]))