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search-for-a-range.py
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search-for-a-range.py
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# Time: O(logn)
# Space: O(1)
class Solution(object):
def searchRange(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
# Find the first idx where nums[idx] >= target
left = self.binarySearch(lambda x, y: x >= y, nums, target)
if left >= len(nums) or nums[left] != target:
return [-1, -1]
# Find the first idx where nums[idx] > target
right = self.binarySearch(lambda x, y: x > y, nums, target)
return [left, right - 1]
def binarySearch(self, compare, nums, target):
left, right = 0, len(nums)
while left < right:
mid = left + (right - left) / 2
if compare(nums[mid], target):
right = mid
else:
left = mid + 1
return left
def binarySearch2(self, compare, nums, target):
left, right = 0, len(nums) - 1
while left <= right:
mid = left + (right - left) / 2
if compare(nums[mid], target):
right = mid - 1
else:
left = mid + 1
return left
def binarySearch3(self, compare, nums, target):
left, right = -1, len(nums)
while left + 1 < right:
mid = left + (right - left) / 2
if compare(nums[mid], target):
right = mid
else:
left = mid
return left if left != -1 and compare(nums[left], target) else right