Add binary search in Kotlin (thuva4#435). (thuva4#436)

abdulwd · thuva4 · commit dd0f0554cc7c · 2017-10-28T06:36:07.000+05:30
diff --git a/BinarySearch/Kotlin/BinarySearchRecursive.kt b/BinarySearch/Kotlin/BinarySearchRecursive.kt
@@ -0,0 +1,36 @@
+fun IntArray.binarySearch(lowerIndex: Int, upperIndex: Int, x: Int): Int {
+    val arr = this
+    if (upperIndex >= lowerIndex) {
+        val mid = lowerIndex + (upperIndex - lowerIndex) / 2
+
+        // If the element is found
+        if (arr[mid] == x)
+            return mid
+
+        /* If the element is smaller than mid, then it can only be present in left subarray
+        else the element can only be present in right subarray */
+        return if (arr[mid] > x) binarySearch(lowerIndex, mid - 1, x)
+        else binarySearch(mid + 1, upperIndex, x)
+    }
+    // We reach here only when the element is not present in array
+    return -1
+}
+
+fun main(args: Array<String>) {
+    println("Enter the size of array:")
+    val n = readLine()!!.toInt()
+    println("Enter the elements of array:")
+    var arr = IntArray(n) { readLine()!!.toInt() }
+    println("Enter a number to search:")
+    val x = readLine()!!.toInt()
+    arr = arr.sortedArray() // Sorting the array in ascending order
+    println("Array in ascending order: ")
+    for (l in arr)
+        print("$l ")
+    println()
+    val result = arr.binarySearch(0, n - 1, x)
+    if (result == -1)
+        println("Element not present")
+    else
+        println("Element found at index $result")
+}
diff --git a/README.md b/README.md
@@ -5,13 +5,13 @@ This repository contains examples of various algorithms which were written on di
 ## Implemented algorithms with languages:
 
 
-Language| Java | Python | Rust | C | C++ | JavaScript  | Go | C# | Ruby | Swift | Racket | Perl | Crystal
----|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
+Language| Java | Python | Rust | C | C++ | JavaScript  | Go | C# | Ruby | Swift | Racket | Perl | Crystal| Kotlin
+---|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
 A*Search |  | :+1: |  |  | :+1: |  |  |  |
 BellmanFord | :+1: |  |  |  | :+1: |  |  |  |
 BestFirstSearch | :+1: | :+1: |  |  |  |  |  |  | :+1: |
 BinaryGCD | :+1: |  |  |  |  |  |  |  |  |
-BinarySearch | :+1: | :+1: |  | :+1: | :+1: | :+1: | :+1: |  | :+1: | :+1:
+BinarySearch | :+1: | :+1: |  | :+1: | :+1: | :+1: | :+1: |  | :+1: | :+1: |  |  |  | :+1:
 Binary Search Modified |  |  |  | :+1: |  |  |  |  |
 Bitap Algorithm |  | :+1: |  |  | :+1: |  |  |  |
 BreadthFirstSearch | :+1: | :+1: |  | :+1: |  |  |  |  |
