leetcode.com 34. Find First and Last Position of Element in Sorted Array

문제 링크: https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array

Author: skysign

leetcode.com 34. Find First and Last Position of Element in Sorted Array/main.py

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+from typing import List
+
+
+class Solution:
+    def searchRange(self, nums: List[int], target: int) -> List[int]:
+        if len(nums) == 0:
+            return [-1, -1]
+
+        idx = self.binary_search(nums, target)
+
+        if idx == -1:
+            return [-1, -1]
+
+        return self.two_pointer(nums, target, idx)
+
+    def binary_search(self, nums: List[int], target: int) -> int:
+        left, right = 0, len(nums) - 1
+
+        while left <= right:
+            mid = (left + right) // 2
+
+            if target == nums[mid]:
+                return mid
+
+            if target < nums[mid]:
+                right = mid - 1
+            else:  # nums[mid] < target
+                left = mid + 1
+
+        return -1
+
+    def two_pointer(self, nums: List[int], target, bgn: int) -> List[int]:
+        left, right = bgn, bgn
+
+        while 0 <= left and nums[left] == target:
+            left -= 1
+
+        left += 1
+
+        while right <= len(nums) - 1 and nums[right] == target:
+            right += 1
+
+        right -= 1
+
+        return [left, right]

leetcode.com 34. Find First and Last Position of Element in Sorted Array/test_main.py

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+from unittest import TestCase
+from main import Solution
+
+
+class TestSolution(TestCase):
+    def test1_search_range(self):
+        sln = Solution()
+        self.assertEqual([3, 4], sln.searchRange([5, 7, 7, 8, 8, 10], 8))
+
+    def test2_search_range(self):
+        sln = Solution()
+        self.assertEqual([-1, -1], sln.searchRange(nums=[5, 7, 7, 8, 8, 10], target=6))
+
+    def test3_search_range(self):
+        sln = Solution()
+        self.assertEqual([-1, -1], sln.searchRange(nums=[], target=0))
+
+    def test4_search_range(self):
+        sln = Solution()
+        self.assertEqual([0, 0], sln.searchRange(nums=[1], target=1))
+
+    def test81_search_range(self):
+        sln = Solution()
+        self.assertEqual([1, 1], sln.searchRange(nums=[1, 4], target=4))