mapReduce.py

#!/usr/bin/python3

def mapReduceTR(f, combine, zero, a, b):
    def loop(a, acc):
        if (a > b):
            return acc
        else:
            return loop(a + 1, combine(f(a), acc))
    return loop(a, zero)

print(mapReduceTR(lambda x: x*x, lambda x,y: x+y, 0, 1, 10))

mapReduce.scala

def mapReduceTR(f: Int => Int, combine: (Int, Int) => Int, zero: Int)(a: Int, b: Int): Int = {
  @tailrec
  def loop(a: Int, acc: Int): Int = {
    if (a > b)
      acc
    else
      loop(a + 1, combine(f(a), acc))
  }
  loop(a, zero)
}

mapReduce(x => x * x, (x, y) => x + y, 0)(a, b)