finished deliverable

search.py

@@ -19,3 +19,36 @@
 Output: 0
 Explanation: -1 exists in the list and its index is 0
 """
+
+# distance = high index - low index
+# middle = low index + (distance // 2)
+
+def binary_search(nums, target):
+    # keep track of the window -- start by assuming the entire list is the window
+    # vars for low index, the high index, middle point index.
+    # continusly iterate until the target is found or we determine the target cannot be found
+        # check the value at the mid point against the target, stop iterating if target is found.
+        # if the value at the midpoint is less than the target, slide the window down.
+    low = 0
+    high = len(nums)
+    mid = high // 2
+
+    while True:
+        if nums[mid] == target:
+            return mid
+        elif nums[mid] > target:
+            high = mid
+            difference = high - low
+            mid = low + (difference // 2)
+        else:
+            low = mid
+            difference = high - low
+            mid = low + (difference // 2)
+        print(f'low:{low}, mid:{mid}, high:{high}')
+        if mid == low:
+            return -1
+
+print(binary_search([-1, 0, 3, 5, 9, 12], 9 ))
+print(binary_search([-1, 0, 3, 5, 9, 12], 2 ))
+print(binary_search([-1, 0, 3, 5, 9, 12], 12 ))
+print(binary_search([-1, 0, 3, 5, 9, 12], -1 ))