Fix search_range and add test (keon#868)

mojjominion · web-flow · commit e24247fb1455 · 2023-03-08T01:32:38.000-08:00
diff --git a/algorithms/search/search_range.py b/algorithms/search/search_range.py
@@ -17,17 +17,17 @@ def search_range(nums, target):
     """
     low = 0
     high = len(nums) - 1
-    while low <= high:
+    # breaks at low == high
+    # both pointing to first occurence of target
+    while low < high:
         mid = low + (high - low) // 2
-        if target < nums[mid]:
-            high = mid - 1
-        elif target > nums[mid]:
-            low = mid + 1
+        if target <= nums[mid]:
+            high = mid
         else:
-            break
+            low = mid + 1
 
     for j in range(len(nums) - 1, -1, -1):
         if nums[j] == target:
-            return [mid, j]
+            return [low, j]
 
     return [-1, -1]
diff --git a/tests/test_search.py b/tests/test_search.py
@@ -91,6 +91,11 @@ def test_search_range(self):
         self.assertEqual([1, 2], search_range(array, 7))
         self.assertEqual([-1, -1], search_range(array, 11))
 
+        array = [5, 7, 7, 7, 7, 8, 8, 8, 8, 10]
+        self.assertEqual([5, 8], search_range(array, 8))
+        self.assertEqual([1, 4], search_range(array, 7))
+        self.assertEqual([-1, -1], search_range(array, 11))
+
     def test_find_min_rotate(self):
         array = [4, 5, 6, 7, 0, 1, 2]
         self.assertEqual(0, find_min_rotate(array))
