# program

## Find a pair in the array whose sum is equal to the given target

Given an array of sorted numbers and a target sum, find a pair in the array whose sum is equal to the given target. Write a function to return the indices of the two numbers (i.e. the pair) such that they add up to the given target. Example 1: Input: [1, 2, 3, 4, 6], target=6 Output: [1, 3] Explanation: The numbers at index 1 and 3 add up to 6: 2+4=6 We can use the Two Pointers approach to solve this. Solution: Time Complexity: O(n) Space Complexity: O(1)

## Understanding Tail recursion in Scala

Tail recursion is little tricky concept in Scala and takes time to master it completely. Before we get into Tail recursion, lets try to look into recursion. A Recursive function is the function which calls itself. If some action is repetitive, we can call the same piece of code again. Recursion could be applied to problems where you use regular loops to solve it. Factorial program with regular loops – [code lang=”scala”] def factorial(n: Int): Int = { var fact = 1 for(i <- 1 to n) { fact = fact * i; } return fact } [/code] The same can be re-written with recursion like below – [code lang=”scala”] def factorialWithRecursion(n: Int): Int = { if (n == 0) return 1 else return n * factorialWithRecursion(n-1) } [/code] In the recursive approach, we return e...