feat: add meta binary search implementation

DIRECTORY.md

@@ -314,6 +314,7 @@
   * [InterpolationSearch](Search/InterpolationSearch.js)
   * [JumpSearch](Search/JumpSearch.js)
   * [LinearSearch](Search/LinearSearch.js)
+  * [MetaBinarySearch](Search/MetaBinarySearch.js)
   * [Minesweeper](Search/Minesweeper.js)
   * [QuickSelectSearch](Search/QuickSelectSearch.js)
   * [RabinKarp](Search/RabinKarp.js)
@@ -322,8 +323,8 @@
   * [TernarySearch](Search/TernarySearch.js)
   * [UnionFind](Search/UnionFind.js)
 * **Sliding-Windows**
-  * [MaxSumSubarrayFixed](Sliding-Windows/MaxSumSubarrayFixed.js)
   * [LongestSubarrayWithSumAtMost](Sliding-Windows/LongestSubarrayWithSumAtMost.js)
+  * [MaxSumSubarrayFixed](Sliding-Windows/MaxSumSubarrayFixed.js)
 * **Sorts**
   * [AlphaNumericalSort](Sorts/AlphaNumericalSort.js)
   * [BeadSort](Sorts/BeadSort.js)

Search/MetaBinarySearch.js

@@ -0,0 +1,28 @@
+/**
+ * Meta Binary Search
+ * https://www.geeksforgeeks.org/meta-binary-search-one-sided-binary-search/
+ *
+ * Builds the index bit by bit from the most-significant bit to the least-significant bit.
+ * Works on sorted arrays and returns the index of target, or -1 if not found.
+ */
+
+function metaBinarySearch(sortedArray, target) {
+  if (!Array.isArray(sortedArray) || sortedArray.length === 0) {
+    return -1
+  }
+
+  const n = sortedArray.length
+  const maxBit = Math.floor(Math.log2(Math.max(1, n - 1)))
+
+  let position = 0
+  for (let bit = maxBit; bit >= 0; bit--) {
+    const candidate = position + 2 ** bit
+    if (candidate < n && sortedArray[candidate] <= target) {
+      position = candidate
+    }
+  }
+
+  return sortedArray[position] === target ? position : -1
+}
+
+export { metaBinarySearch }

Search/test/MetaBinarySearch.test.js

@@ -0,0 +1,28 @@
+import { metaBinarySearch } from '../MetaBinarySearch'
+
+describe('Meta Binary Search', () => {
+  test('returns index for found numeric element', () => {
+    expect(metaBinarySearch([2, 5, 8, 12, 16, 23, 38], 23)).toBe(5)
+  })
+
+  test('returns -1 when numeric element is missing', () => {
+    expect(metaBinarySearch([2, 5, 8, 12, 16, 23, 38], 9)).toBe(-1)
+  })
+
+  test('works with sorted strings', () => {
+    expect(metaBinarySearch(['alpha', 'beta', 'delta', 'omega'], 'delta')).toBe(
+      2
+    )
+  })
+
+  test('returns index for a matching element in a single-element array', () => {
+    expect(metaBinarySearch([7], 7)).toBe(0)
+  })
+  test('returns -1 on empty input', () => {
+    expect(metaBinarySearch([], 1)).toBe(-1)
+  })
+
+  test('returns index for a matching element in a single-element array', () => {
+    expect(metaBinarySearch([7], 7)).toBe(0)
+  })
+})