Square(n) Sum
def squareSum(xs: List[Int]): Int = xs.map(x => x*x).sum

String repeat
def repeatStr(times: Int, str: String) = str * times

Counting sheep...
def countSheep(sheep: Array[Boolean]): Int = sheep.count(_ == true)

Even or Odd
def evenOrOdd(number: Int): String = if (number % 2 == 0) "Even" else "Odd"

Convert boolean values to strings 'Yes' or 'No'.
def boolToWord(boolean: Boolean): String = if (boolean) "Yes" else "No"

Reversed Strings
def solution(word: String): String = word.reverse  

Subtract the sum
def subtractSum(n: Int) = "apple" // почему так - доказывайте сами, мне лень

Transportation on vacation
def cost(days: Int): Int = if(days >=7) days*40-50 else
    if(days>=3) days*40-20 else
    40*days

Century From Year
def centuryFromYear(year: Int): Int = (year-1)/100+1
or
def centuryFromYear(year: Int): Int = (year + 99) / 100

Convert a Number to a String!
def numberToString(n: Int): String = n.toString

Twice as old
def twice_as_old(dad: Int, son: Int) = (dad - 2 * son).abs
or
def twice_as_old(dad: Int, son: Int) = math.abs(2 * son - dad)

Beginner Series #2 Clock
def past(h: Int, m: Int, s: Int): Int = h*3600000+m*60000+s*1000

Simple multiplication
def multiply(n: Int): Int = if(n%2==0) n*8 else n*9

Is n divisible by x and y?
def isDivisible(n: Int, x: Int, y: Int): Boolean = n % x == 0 && n % y == 0

Return Negative
def makeNegative(n: Int): Int = -n.abs
or
def makeNegative(n: Int): Int = -math.abs(n)

Grasshopper - Terminal game move function
def move(pos: Int, roll: Int): Int = pos + 2 * roll

Expressions Matter
def expressionMatter(a: Int, b: Int, c: Int): Int = List(a+b+c, (a+b)*c,a*(b+c),a*b*c, a*b+c, a+b*c).max

Opposite number
def opposite(number: Double): Double = -number

Opposites Attract
def lovefunc(flower1: Int, flower2: Int): Boolean = (flower1 + flower2) % 2 == 1
or
def lovefunc(flower1: Int, flower2: Int): Boolean = flower1 % 2 != flower2 % 2

Grasshopper - Summation
def summation(n: Int): Int = n * (n + 1) / 2

Remove First and Last Character
def removeChars(s: String): String = s.substring(1, s.length - 1)
or
def removeChars(s: String): String = s.tail.init

Find the smallest integer in the array
def findSmallestInt(nums:List[Int]):Int = nums.min

Returning Strings
def greet(name: String): String = "Hello, "+name+" how are you doing today?"
or
def greet(name: String): String = s"Hello, $name how are you doing today?"

Reversed Words
def reverseWords(str: String): String = str.split(' ').reverse.mkString(" ")

You only need one - Beginner
def check(seq:List[Any], elem: Any) = seq.contains(elem)

Sum of positive
def positiveSum(arr: Array[Int]): Int = arr.filter(x => x > 0).sum
or
def positiveSum(arr: Array[Int]): Int = arr.filter(_ > 0).sum

Beginner - Lost Without a Map
def maps(xs: List[Int]): List[Int] = xs.map(_ * 2)

My head is at the wrong end!
def fixTheMeerkat(arr: List[String]): List[String] = arr.reverse

Count of positives / sum of negatives
def countPositivesSumNegatives(xs: Array[Int]): (Int, Int) = (xs.count(_ > 0), xs.filter(_ < 0).sum)

Remove String Spaces
def noSpace(s: String): String = s.replace(" ", "")

Regular Ball Super Ball
class Ball(val ballType: String = "regular")
or
class Ball(bType: String="regular")
  {
    var ballType:String = bType
  }

A wolf in sheep's clothing
def warnTheSheepCheck(queue: Array[String]): String = if (queue.last == "wolf") 
      "Pls go away and stop eating my sheep" else 
      s"Oi! Sheep number ${queue.reverse.indexOf("wolf")}! You are about to be eaten by a wolf!"

Beginner - Reduce but Grow
def grow(xs: List[Long]): Long = xs.product
or
def grow(xs: List[Long]): Long = if(xs.isEmpty) return 1
    xs.head*grow(xs.tail)

Removing Elements
def removeEveryOther[T](list: List[T]): List[T] = list.grouped(2).map(_.head).toList
or
def removeEveryOther[T](list: List[T]): List[T] = list.zipWithIndex.collect { case (x, i) if i%2==0 => x }

Grasshopper - Check for factor
def checkForFactor(base: Int, factor: Int): Boolean = base % factor == 0

Count Odd Numbers below n
def oddCount(n: Long): Long = n / 2

If you can't sleep, just count sheep!!
def countingSheep(n: Int): String = (1 to n).map(i => s"$i sheep...").mkString

Pillars
def distance(num_pill: Int, dist: Int, width: Int ): Int = if (num_pill == 1) 0 else
    ((num_pill - 1) * dist * 100) + ((num_pill - 2) * width)

Thinkful - Number Drills: Pixelart planning
def isDivisible(wallLength: Int, pixelSize: Int): Boolean = wallLength % pixelSize == 0