clean up repo.

add more notes

chapter1/README.md

@@ -0,0 +1,5 @@
+# Binary Search
+
+Repeatedly split the array checking if value is greater or less than the mid point. Stop when the exact value is found.
+
+It takes log N steps to reduce an array of size N to an array of size 1. Time complexity for this algorithm is `O(log N)`.

chapter1/binary.py

@@ -30,11 +30,14 @@ SAMPLE_SIZE = 1000
 numbers = random.sample(range(LOWER, UPPER), SAMPLE_SIZE)
 numbers.sort()
 
+seen = set()
+count = 0
 result = None
-while result is None:
+while not result:
     guess = random.randrange(LOWER, UPPER)
-    logger.debug(f"guess: {guess}")
-    result = binary_search(numbers, guess)
+    if guess not in seen:
+        count += 1
+        seen.add(guess)
+        result = binary_search(numbers, guess)
 
-
-print(f"Found {guess} at index {result}.")
+print(f"Found {guess} at index {result} after {count} attempts")

chapter1/ex1.1.py

@@ -1,7 +0,0 @@
-import math
-
-num_steps = int(math.log2(128))
-print(
-    f"A binary search would take maximum {num_steps} steps "
-    "to search a list of 128 items."
-)

chapter1/ex1.2.py

@@ -1,7 +0,0 @@
-import math
-
-num_steps = int(math.log2(128*2))
-print(
-    f"A binary search would take maximum {num_steps} steps "
-    "to search a list of 256 items."
-)