initial commit

leetcode/33_search_in_rotated_array.py

@@ -0,0 +1,35 @@
+import pytest
+
+
+class Solution:
+    def search(self, nums: list[int], target: int) -> int:
+        # The first item of first ascending sequence is always bigger than the first item of the second ascending sequence.
+        low, high = 0, len(nums) - 1
+        while low <= high:
+            mid = low + (high - low) // 2
+            if nums[mid] == target:
+                return mid
+
+            # If the current item is bigger than the first item of the first ascending sequence we know that nums[low:mid] is sorted.
+            # Otherwise we know that the current mid is on the edge of the second ascending sequence.
+            if nums[mid] >= nums[low]:
+                if nums[low] <= target <= nums[mid]:
+                    high = mid - 1
+                else:
+                    low = mid + 1
+            else:
+                if nums[mid] <= target <= nums[high]:
+                    low = mid + 1
+                else:
+                    high = mid - 1
+
+        return -1
+
+
+@pytest.fixture
+def solution():
+    return Solution()
+
+
+def test_search(solution: Solution):
+    assert solution.search([4, 5, 6, 7, 0, 1, 2], 0) == 4

leetcode/34_find_first_and_last_position_of_element_in_sorted_array.py

@@ -0,0 +1,47 @@
+import typing
+import pytest
+
+FindFn = typing.Callable[[int], bool]
+
+
+class Solution:
+    def searchRange(self, nums: list[int], target: int) -> list[int]:
+        start = self.binary_search(nums, target, lambda v: v >= target)
+        end = self.binary_search(nums, target, lambda v: v > target)
+        return [start, end]
+
+    def binary_search(self, nums: list[int], target: int, fn: FindFn) -> int:
+        res = -1
+        low, high = 0, len(nums) - 1
+        while low <= high:
+            mid = low + (high - low) // 2
+            if nums[mid] == target:
+                res = mid
+
+            if fn(nums[mid]):
+                high = mid - 1
+            else:
+                low = mid + 1
+
+        return res
+
+
+@pytest.fixture
+def solution():
+    return Solution()
+
+
+@pytest.mark.parametrize(
+    "nums, target, expected",
+    [
+        ([5, 7, 7, 8, 8, 10], 8, [3, 4]),
+        ([5, 7, 7, 8, 8, 10], 6, [-1, -1]),
+        ([], 0, [-1, -1]),
+        ([1], 1, [0, 0]),
+        ([2, 2], 2, [0, 1]),
+    ],
+)
+def test_search_range(
+    solution: Solution, nums: list[int], target: int, expected: list[int]
+):
+    assert solution.searchRange(nums, target) == expected