add binary search

chapter1/binary.py

@@ -0,0 +1,46 @@
+import logging
+import random
+import time
+
+logging.basicConfig(level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+
+LOWER = 1000
+UPPER = 1000000
+SAMPLE_SIZE = 1000
+
+
+def binary_search(arr, item):
+    count = 1
+    low = 0
+    high = len(arr) - 1
+
+    while low <= high:
+        mid = (low + high) // 2
+        guess = arr[mid]
+        if guess == item:
+            logger.debug(f"found item after {count} splits")
+            return mid
+        elif guess > item:
+            high = mid - 1
+        else:
+            low = mid + 1
+
+        count += 1
+
+    return None
+
+
+numbers = random.sample(range(LOWER, UPPER), SAMPLE_SIZE)
+numbers.sort()
+logger.debug(numbers)
+
+start = time.time()
+res = None
+while res is None:
+    guess = random.randrange(LOWER, UPPER)
+    res = binary_search(numbers, guess)
+
+
+print(f"Found {guess} at index {res}. Running time {time.time() - start}")