Added binary search package

Added "find prefix" problem set.
Implemented straight-forward approach and test cases.
Test fixtures are generated using https://random.org/

Author: shorodilov

pyproject.toml

@@ -32,6 +32,7 @@ classifiers = [
     "Topic :: Education",
 ]
 packages = [
+    { include = "bisearch", from = "src" },
     { include = "conv_store", from = "src" },
     { include = "sequences", from = "src" },
     { include = "sorting", from = "src" },

src/bisearch/__init__.py

@@ -0,0 +1,66 @@
+from typing import List
+
+
+def bisect_right(origin: List[str], search: str = "") -> int:
+    """Return the most right index
+
+    :param origin: a list of strings
+    :type origin: list[str]
+    :param search: a prefix to search
+    :type search: str
+
+    :return: the index of the first string starting with search prefix
+    :rtype: int
+
+    """
+
+    low: int = 0
+    high: int = len(origin)
+    prefix_size: int = len(search)
+
+    while low < high:
+        idx = low + (high - low) // 2  # the same as (high + low) // 2
+        cur = origin[idx][:prefix_size]
+
+        if cur <= search:
+            low = idx + 1
+        else:
+            high = idx
+
+    return low
+
+
+def bisect_left(origin: List[str], search: str = "") -> int:
+    """Return the most left index
+
+    :param origin: a list of strings
+    :type origin: list[str]
+    :param search: a prefix to search
+    :type search: str
+
+    :return: the index after the last string starting with search prefix
+    :rtype: int
+
+    """
+
+    low: int = 0
+    high: int = len(origin)
+    prefix_size: int = len(search)
+
+    while low < high:
+        idx = low + (high - low) // 2  # the same as (high + low) // 2
+        cur = origin[idx][:prefix_size]
+
+        if cur < search:
+            low = idx + 1
+        else:
+            high = idx
+
+    return low
+
+
+def find_all(origin: List[str], search: str = "") -> List[str]:
+    start = bisect_left(origin, search)
+    end = bisect_right(origin, search)
+
+    return origin[start:end]

src/bisearch/prefix.py

@@ -0,0 +1,29 @@
+from pathlib import Path
+
+import pytest
+
+
+@pytest.fixture
+def strings_fixtures():
+    fixture_path = Path(__file__).parent.joinpath("fixtures/strings.txt")
+    with open(fixture_path) as fixture_file:
+        return fixture_file.read().splitlines()
+
+
+@pytest.fixture
+def fa_fixture():
+    return (
+        "ua",
+        ["uaeafwqbag", "uasyolgnuc", "uaszazvdez", "uavmfgakey", "uawwitgssy",
+         "uaxxgxmsrn", "uayppkjtny", ]
+    )
+
+
+@pytest.fixture
+def pr_fixture():
+    return "sh", 7045
+
+
+@pytest.fixture
+def pl_fixture():
+    return "vp", 8291