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34-find-first-and-last-position-of-element-in-sorted-array/34-find-first-and-last-position-of-element-in-sorted-array.py

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+class Solution(object):
+    def searchRange(self, nums, target):
+        """
+        :type nums: List[int]
+        :type target: int
+        :rtype: List[int]
+        """
+        # Base cases
+        if len(nums) == 0:
+            return [-1,-1]
+        
+        if nums[0] > target:
+            return [-1,-1]
+        
+        if nums[-1] < target:
+            return [-1,-1]
+        
+        if len(nums) == 1:
+            return [0,0] if nums[0] == target else [-1,-1]
+        
+        foundIndex = -1
+        
+        # Searchable region bounds
+        searchLow = 0
+        searchHigh = len(nums) - 1
+        
+        # Find an instance of target
+        while searchLow < searchHigh:
+            # Base case: length of bounds = 1
+            if searchHigh - searchLow == 1:
+                if nums[searchLow] == target:
+                    foundIndex = searchLow
+                elif nums[searchHigh] == target:
+                    foundIndex = searchHigh
+                break
+            
+            # Standard search
+            midpointIndex = int((searchHigh - searchLow) / 2) + searchLow
+            if nums[midpointIndex] == target:
+                foundIndex = midpointIndex
+                break
+            elif nums[midpointIndex] < target:
+                searchLow = midpointIndex
+            else:
+                searchHigh = midpointIndex
+                
+        # Target not found
+        if nums[foundIndex] != target:
+            return [-1,-1]
+                
+        # Find all occurances of target
+        firstOcc = foundIndex
+        lastOcc = foundIndex
+        while firstOcc - 1 >= 0 and nums[firstOcc - 1] == target:
+            firstOcc -= 1
+            
+        while lastOcc + 1 < len(nums) and nums[lastOcc + 1] == target:
+            lastOcc += 1
+            
+        return [firstOcc, lastOcc]