Merge pull request #333 from RitikDua/master

raklaptudirm · web-flow · commit 34a1eb246105 · 2021-05-23T14:27:08.000+05:30
Added BinarySearchIterative Function
diff --git a/Search/BinarySearch.js b/Search/BinarySearch.js
@@ -7,7 +7,7 @@
  * value is found or the interval is empty.
  */
 
-function binarySearch (arr, x, low = 0, high = arr.length - 1) {
+function binarySearchRecursive (arr, x, low = 0, high = arr.length - 1) {
   const mid = Math.floor(low + (high - low) / 2)
 
   if (high >= low) {
@@ -18,16 +18,36 @@ function binarySearch (arr, x, low = 0, high = arr.length - 1) {
 
     if (x < arr[mid]) {
       // arr[mid] is an upper bound for x, so if x is in arr => low <= x < mid
-      return binarySearch(arr, x, low, mid - 1)
+      return binarySearchRecursive(arr, x, low, mid - 1)
     } else {
       // arr[mid] is a lower bound for x, so if x is in arr => mid < x <= high
-      return binarySearch(arr, x, mid + 1, high)
+      return binarySearchRecursive(arr, x, mid + 1, high)
     }
   } else {
     // if low > high => we have searched the whole array without finding the item
     return -1
   }
 }
+function binarySearchIterative (arr, x, low = 0, high = arr.length - 1) {
+  while (high >= low) {
+    const mid = Math.floor(low + (high - low) / 2)
+
+    if (arr[mid] === x) {
+      // item found => return its index
+      return mid
+    }
+
+    if (x < arr[mid]) {
+      // arr[mid] is an upper bound for x, so if x is in arr => low <= x < mid
+      high = mid - 1
+    } else {
+      // arr[mid] is a lower bound for x, so if x is in arr => mid < x <= high
+      low = mid + 1
+    }
+  }
+  // if low > high => we have searched the whole array without finding the item
+  return -1
+}
 
 /* ---------------------------------- Test ---------------------------------- */
 
@@ -61,10 +81,10 @@ const stringArr = [
   'Zulu'
 ]
 
-console.log(binarySearch(arr, 3))
-console.log(binarySearch(arr, 7))
-console.log(binarySearch(arr, 13))
+console.log(binarySearchRecursive(arr, 3))
+console.log(binarySearchIterative(arr, 7))
+console.log(binarySearchRecursive(arr, 13))
 
-console.log(binarySearch(stringArr, 'Charlie'))
-console.log(binarySearch(stringArr, 'Zulu'))
-console.log(binarySearch(stringArr, 'Sierra'))
+console.log(binarySearchIterative(stringArr, 'Charlie'))
+console.log(binarySearchRecursive(stringArr, 'Zulu'))
+console.log(binarySearchIterative(stringArr, 'Sierra'))
