Binary search in python

python/15_bsearch/bsearch.py

@@ -0,0 +1,22 @@
+"""
+    Author: Wenru
+"""
+
+from typing import List
+
+def bsearch(nums: List[int], target: int) -> int:
+    """Binary search of a target in a sorted array
+    without duplicates. If such a target does not exist,
+    return -1, othewise, return its index.
+    """
+    low, high = 0, len(nums) - 1
+    while low <= high:
+        mid = low + (high - low) // 2
+        if nums[mid] == target:
+            return mid
+        elif nums[mid] < target:
+            low = mid + 1
+        else:
+            high = mid - 1
+    
+    return -1