Hackerrank - Pascal's Triangle

Problem Statement
A description of the problem can be found on Hackerrank.

Solution
I created recursive function for factorial

$fact$

.
Then create all combinations of rows and column indexes. For input 4 it looks like:

(0,0)
(1,0), (1,1)
(2,0), (2,1), (2,2)
(3,0), (3,1), (3,2), (3,3)

(0,0)

(1,0), (1,1)

(2,0), (2,1), (2,2)

(3,0), (3,1), (3,2), (3,3)

Apply function for pascal triangle

$\frac{fact(row)}{fact(column) \times fact(row - column)}$

for each combination.

I created solution in Scala:
The solution is also available on my GitHub.

Scala

object PascalTriangle extends App {

   val k = io.Source.stdin.bufferedReader().readLine().toInt

   (0 until k).foreach {
     row =>
       println(List.range(0, row + 1)
         .map(col =>
         fact(row) / (fact(col) * fact(row - col)))
         .mkString(" "))
   }

   def fact(n: Int): Int = {
     if(n <= 1) 1
     else n * fact(n - 1)
   }
 }

object PascalTriangle extends App {

val k = io.Source.stdin.bufferedReader().readLine().toInt

(0 until k).foreach {

row =>

println(List.range(0, row + 1)

.map(col =>

fact(row) / (fact(col) * fact(row - col)))

.mkString(" "))

}

def fact(n: Int): Int = {

if(n <= 1) 1

else n * fact(n - 1)

}

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Pascal’s Triangle