Merge pull request #447 from sakshamsachdeva/master

Binary Search in Kotlin #445

Author: probot-auto-merge[bot]

Kotlin/BinarySearch.kt

@@ -0,0 +1,23 @@
+fun main(args: Array<String>) {
+    val input = readLine()!!.trim().split(" ").map { it -> it.toInt() }.toIntArray()    // to read an array (from user input)
+    val eleToSearch = readLine()!!.trim().toInt()   // to read the element to be searched (from user input)
+    val pos = binarySearchRecursive(input, eleToSearch, 0, input.size -1)
+    if(pos >= 0 ) {
+        println(pos)    // to print position at last
+    } else {
+        println("Position not found")
+    }
+}
+
+fun binarySearchRecursive(input: IntArray, eleToSearch: Int, low:Int, high:Int): Int {
+
+    while(low <=high) {
+      val mid = (low + high) /2
+        when {
+            eleToSearch > input[mid] -> return binarySearchRecursive(input, eleToSearch, mid+1, high)   // element is greater than middle element of array, so it will be in right half. Recursion will call the right half again
+            eleToSearch < input[mid] -> return binarySearchRecursive(input, eleToSearch, low, mid-1)    //element is less than middle element of array, so it will be in left half of the array. Recursion will call the left half again.
+            eleToSearch == input[mid] -> return mid // element found.
+        }
+    }
+    return -1
+}