# Follow up for "Search in Rotated Sorted Array":
# What if duplicates are allowed?
#
# Would this affect the run-time complexity? How and why?
# Suppose an array sorted in ascending order is rotated
# at some pivot unknown to you beforehand.
#
# (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
#
# Write a function to determine if a given target is in the array.
#
# The array may contain duplicates.
相比 [leetcode: 33. Search in Rotated Sorted Array] ,区别在于:
当 x[mid] = x[left] 时,很难判断 target 会落在哪,那么只能采取 left+=1
leetcode: 33. Search in Rotated Sorted Array
class Solution():
def search(self, x, target):
left, right = 0, len(x) - 1
while left <= right:
mid = (left + right) // 2
if x[mid] == target:
return True
elif x[mid] == x[left]: # x[mid] = x[left] 时,很难判断 target 会落在哪,那么只能采取 left+=1
left += 1
elif x[left] <= target < x[mid] or (x[left] > x[mid] and not x[mid] < target <= x[right]):
right = mid - 1
else:
left = mid + 1
return False
if __name__ == "__main__":
assert Solution().search([3, 5, 1], 3) == True
assert Solution().search([2, 2, 3, 3, 4, 1], 1) == True
assert Solution().search([4, 4, 5, 6, 7, 0, 1, 2], 5) == True