feat: add binary search origin algorithm

Search/BinarySearch.js

@@ -49,4 +49,52 @@ function binarySearchIterative(arr, x, low = 0, high = arr.length - 1) {
   return -1
 }
 
-export { binarySearchIterative, binarySearchRecursive }
+/* binary search for unsorted arrays, returns original index. */
+function binarySearchOrigin(arr, target) {
+  // check if all elements in the array are of the same type
+  const firstType = typeof arr[0]
+  const allSameType = arr.every((item) => typeof item === firstType)
+
+  if (!allSameType) {
+    return 'Cannot perform search: Array contains elements of different types.'
+  }
+
+  const originalArrayWithIndices = arr.map((value, index) => ({
+    value,
+    index
+  }))
+
+  // sorting function based on type (number or string)
+  const sortedArrayWithIndices = originalArrayWithIndices.sort((a, b) => {
+    if (typeof a.value === 'number' && typeof b.value === 'number') {
+      return a.value - b.value // sort numbers
+    } else if (typeof a.value === 'string' && typeof b.value === 'string') {
+      return a.value.localeCompare(b.value) // sort strings
+    }
+  })
+
+  let start = 0
+  let end = sortedArrayWithIndices.length - 1
+
+  // binary search loop
+  while (start <= end) {
+    const midIndex = Math.floor((start + end) / 2)
+    const mid = sortedArrayWithIndices[midIndex].value
+
+    if (mid === target) {
+      // return the original index if the target is found
+      return sortedArrayWithIndices[midIndex].index
+    }
+
+    if (mid < target) {
+      start = midIndex + 1
+    } else {
+      end = midIndex - 1
+    }
+  }
+
+  // return -1 if target is not found
+  return -1
+}
+
+export { binarySearchIterative, binarySearchRecursive, binarySearchOrigin }

Search/test/BinarySearch.test.js

@@ -1,4 +1,8 @@
-import { binarySearchIterative, binarySearchRecursive } from '../BinarySearch'
+import {
+  binarySearchIterative,
+  binarySearchRecursive,
+  binarySearchOrigin
+} from '../BinarySearch'
 
 const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 const stringArr = [
@@ -31,7 +35,11 @@ const stringArr = [
 ]
 
 describe('Binary Search', () => {
-  const funcs = [binarySearchIterative, binarySearchRecursive]
+  const funcs = [
+    binarySearchIterative,
+    binarySearchRecursive,
+    binarySearchOrigin
+  ]
   for (const func of funcs) {
     test('expect to return the index of the item in the array', () => {
       expect(func(arr, 3)).toBe(2)