DSA fundamentals problem solving-1

// Write a function called getSum that takes in two numbers and returns the sum of those two numbers
function getSum(num1, num2) {
  return num1 + num2
  //write function
}

// console.log(getSum(1, 2)) // 3
// getSum(10, 5) // 15
// getSum(2, 2) // 4
// getSum(10, 5) // 15

//=================================================

// Write a function called calculator that takes in 2 numbers and an operator and returns the result of the calculation.
function calculator(num1, num2, operator) {
  //   let result
  //   switch (operator) {
  //     case '+':
  //       result = num1 + num2
  //       break
  //     case '-':
  //       result = num1 - num2
  //       break
  //     case '*':
  //       result = num1 * num2
  //       break
  //     case '/':
  //       result = num1 / num2
  //       break
  //     default:
  //       throw new Error('Not a valid Operator')
  //   }

  if (operator === '+') {
    return num1 + num2
  }
  if (operator === '-') return num1 - num2
  if (operator === '*') return num1 * num2
  if (operator === '/') return num1 / num2
  throw new Error('Not a valid Operator')

  //   return result
}

console.log(calculator(1, 2, '*')) // 3
// calculator(10, 5, '-') // 5
// calculator(2, 2, '*') // 4
// calculator(10, 5, '/') // 2

//=================================================

// Write a function called countOccurrences that takes in a string and a character and returns the number of occurrences of that character in the string.
// Lowercase and uppercase characters are considered different characters
function countOccurrences(str, char) {
  //write code here
  let count = 0
  for (let letter of str) {
    letter === char && count++
  }
  return count
}

console.log(countOccurrences('hello', 'l')) //2
// countOccurrences('hello', 'z') // 0

// You may assume that each word consists of only letters and spaces
function titleCase(str) {
  //write code here
  //make all sentence lowecase
  //   const lowecaseStr = str.toLowerCase()
  //   console.log(lowecaseStr)

  //   //devide by space (split)
  //   const splitStr = lowecaseStr.split(' ')
  //   console.log(splitStr)
  //   //make each array elements first letter to uppercase
  //   for (let i = 0; i < splitStr.length; i++) {
  //     splitStr[i] = splitStr[i][0].toUpperCase() + splitStr[i].slice(1)
  //   }
  //   console.log(splitStr)
  //  return splitStr.join(' ')
  return str.replace(/\b\w/g, (match) => match.toUpperCase())
}

console.log(titleCase("I'm a little tea pot")) // I'm A Little Tea Pot
// titleCase('sHoRt AnD sToUt'); // Short And Stout
// titleCase('HERE IS MY HANDLE HERE IS MY SPOUT'); // Here Is My Handle Here Is My Spout

//=================================================

// Write a function called removeDuplicates that takes in an array and returns a new array with duplicates removed.
// function removeDuplicates(arr) {
// const resultSet = new Set(arr)
// console.log(Array.from(resultSet))
// return Array.from(resultSet)

//   const resultArr = []

//   for (let num of arr) {
//     if (!resultArr.includes(num)) {
//       resultArr.push(num)
//     }
//   }

//   console.log(resultArr)
// }

// removeDuplicates([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) // [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// removeDuplicates([1, 1, 1, 1, 1, 1, 1, 1, 1, 1]) // [1]
// removeDuplicates([1, 2, 3, 4, 5, true, 1, 'hello' 2, 3, 'hello', true]); // [1, 2, 3, 4, 5, true, 'hello']

//=================================================

// Write a function called arrayIntersection that takes in two arrays and returns an array containing the intersection of the two input arrays (i.e., the common elements that appear in both arrays).

function arrayIntersection(arr1, arr2) {
  //   const resultArr = []

  //   for (let num of arr1) {
  //     console.log(num)
  //     if (arr2.includes(num)) {
  //       resultArr.push(num)
  //     }
  //   }

  //   console.log(Array.from(new Set(resultArr)))
  const set1 = new Set(arr1)
  const intersectionArr = []

  for (let num of arr2) {
    console.log(num)
    if (set1.has(num)) {
      intersectionArr.push(num)
    }
  }
  return intersectionArr
}

console.log(arrayIntersection([1, 2, 3, 3, 4, 5], [1, 3, 5, 7, 9])) // should return [1, 3, 5]
// arrayIntersection([1, 1, 1, 1, 1], [2, 2, 2, 2, 2]); // should return []
// arrayIntersection([1, 2, 3, 4, 5], [5, 4, 3, 2, 1]); // should return [1, 2, 3, 4, 5]

//=================================================

// Write a function called displayLikes that takes in an array of names and returns a string of who likes the post.

// The function should return a string formatted as follows:

// If no one likes it, it should return 'no one likes this'
// If one person likes it, it should return '{name} likes this'
// If two people like it, it should return '{name1} and {name2} like this'
// If three people like it, it should return '{name1}, {name2} and {name3} like this'
// If more than three people like it, it should return '{name1}, {name2} and {x} others like this'

function displayLikes(namesArr) {
  // Get the length of the array
  const length = namesArr.length

  // Return the appropriate string based on the length of the array
  if (length === 0) {
    return 'no one likes this'
  } else if (length === 1) {
    return `${namesArr[0]} likes this`
  } else if (length === 2) {
    return `${namesArr[0]} and ${namesArr[1]} like this`
  } else if (length === 3) {
    return `${namesArr[0]}, ${namesArr[1]} and ${namesArr[2]} like this`
  } else {
    return `${namesArr[0]}, ${namesArr[1]} and ${length - 2} others like this`
  }
}

// displayLikes([]) // 'no one likes this'
// displayLikes(['Peter']) // 'Peter likes this'
// displayLikes(['Jacob', 'Alex']) // 'Jacob and Alex like this'
// displayLikes(['Max', 'John', 'Mark']) // 'Max, John and Mark like this'
console.log(displayLikes(['Alex', 'Jacob', 'Mark', 'Max'])) // 'Alex, Jacob and 2 others like this'
// displayLikes(['Alex', 'Jacob', 'Mark', 'Max', 'Jill']) // 'Alex, Jacob and 3 others like this'

//=================================================
// Write a function called findMissingNumber that takes in an array of unique numbers from 1 to n (inclusive), where one number is missing. It should return the missing number.

// If an empty array is passed in, it should return 1
// If nothing is passed in, it should return undefined

function findMissingNumber(arr) {
  //write code here
  if (!arr || !Array.isArray(arr)) return undefined
  if (arr.length === 0) return 1

  const n = arr.length + 1

  const expectedSum = (n * (n + 1)) / 2
  console.log(expectedSum)

  //   let total = 0
  //   for(let num of arr){
  //     total += num
  //   }
  //   console.log(total)
  const totalSum = arr.reduce((total, num) => total + num, 0)

  console.log(expectedSum - totalSum)
  return expectedSum - totalSum
  //(n * (n +1)) / 2
}

console.log(findMissingNumber([1, 2, 3, 4, 6, 7, 8, 9, 10])) // 5
// findMissingNumber([10, 8, 6, 7, 5, 4, 2, 3, 1]); // 9
// findMissingNumber([10, 5, 1, 2, 4, 6, 8, 3, 9]); // 7

//=================================================

// Write a function called findMissingLetter that takes in an array of consecutive (increasing) letters as input and returns the missing letter in the array.

function findMissingLetter(arr) {
  const alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
  const startIndex = alphabet.indexOf(arr[0])

  for (let i = 0; i < arr.length; i++) {
    if (arr[i] !== alphabet[startIndex + i]) {
      return alphabet[startIndex + i]
    }
  }

  //write code here
}

console.log(findMissingLetter(['a', 'b', 'c', 'd', 'f'])) // => "e"
// findMissingLetter(['O', 'Q', 'R', 'S']); // => "P"
// findMissingLetter(['t', 'u', 'v', 'w', 'x', 'z']); // => "y"

//=================================================

// Write a function called validateEmail that takes in a string and returns whether the string is a valid email address. For the purposes of this challenge, a valid email address is defined as a string that contains an @ symbol and a . symbol.

function validateEmail(email) {
  //   const emailRegex = /^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$/
  //   return emailRegex.test(email)
  // Check if the email contains the "@" symbol
  //   if (email.indexOf('@') === -1) {
  //     return false
  //   }
  //   // Split the email into the local part and domain
  //   const [localPart, domain] = email.split('@')
  //   // Check if the local part and domain meet the minimum length requirements
  //   if (localPart.length === 0 || domain.length < 3) {
  //     return false
  //   }
  //   // Check if the domain extension consists of at least two characters
  //   const domainExtension = domain.split('.')
  //   if (domainExtension.length < 2 || domainExtension[1].length < 2) {
  //     return false
  //   }
  //   // If all checks pass, return true
  //   return true
  //write code here
}

console.log(validateEmail('john@gmail.com')) // true
validateEmail('john@gmail') // false

//=================================================

// Write a function called diceGameSimulation that simulates this dice game. The function should take one argument:

// numSimulations: The number of times to simulate the dice game.
// The game rules are if a 7 or 11 are rolled, the player wins and they get a result of win. If a 2, 3 or 12 are rolled they lose and get a result of lose. Anything else and they get a result of roll again.

// The function should return an array of objects, where each object represents a simulation result. Each object should contain the following properties:

// dice1: The value of the first dice (a random number between 1 and 6).
// dice2: The value of the second dice (a random number between 1 and 6).
// sum: The sum of the two dice values.
// result: The result of the roll, which can be "win", "lose", or "roll again".

function rollDice() {
  return Math.floor(Math.random() * 6 + 1)
}
function diceGameSimulation(numOfTry) {
  const results = []
  //write code here
  for (let i = 0; i < numOfTry; i++) {
    const dice1 = rollDice()
    const dice2 = rollDice()
    const sum = dice1 + dice2
    let result = ''
    if (sum === 7 || sum === 11) {
      result = 'win'
    } else if (sum === 2 || sum === 3 || sum === 12) {
      result = 'lose'
    } else {
      result = 'Roll Again'
    }
    results.push({ dice1, dice2, sum, result })
  }

  console.log(results)
}

diceGameSimulation(10)

/*
  { dice1: 1, dice2: 5, sum: 6, result: 'roll again' },
  { dice1: 5, dice2: 6, sum: 11, result: 'win' },
  { dice1: 1, dice2: 1, sum: 2, result: 'lose' }
*/

// Write a function called formatPhoneNumber that takes in an array of numbers and returns a string representing the phone number formed by concatenating the numbers in the specified format.

//=================================================

function formatPhoneNumber(numbers) {
  //write code here
  // Get the first 3 numbers and join them together
  const areaCode = numbers.slice(0, 3).join('')
  // Get the next 3 numbers and join them together
  const prefix = numbers.slice(3, 6).join('')
  // Get the last 4 numbers and join them together
  const lineNumber = numbers.slice(6).join('')
  console.log(`(${areaCode}) ${prefix}-${lineNumber}`)
  return `(${areaCode}) ${prefix}-${lineNumber}`

}

formatPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0]); // => "(123) 456-7890"
// formatPhoneNumber([5, 1, 9, 5, 5, 5, 4, 4, 6, 8]); // => "(519) 555-4468"
// formatPhoneNumber([3, 4, 5, 5, 0, 1, 2, 5, 2, 7]); // => "(345) 501-2527"