leetcode_033.py

# leetcode 33. 搜索旋转排序数组

class Solution(object):
    def search(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        #先找到两个第二个升序数组的第一项的
        l = 0
        r = len(nums) -1
        while l < r:
            mid = (l + r)//2
            if nums[mid] > nums[r]:
                l = mid + 1
            else:
                r = mid
        pol = l
        ans = self.binary_search(target, nums[:pol])
        if ans == -1:
            ans = self.binary_search(target, nums[pol:])
            if ans != -1:
                ans += len(nums[:pol])
 
        return ans
    # 二分查找index值函数
    def binary_search(self, target, nums):
        index = -1
        l = 0
        r = len(nums) - 1
        while l <= r:
            mid = (l+r)//2
            if nums[mid] < target:
                l = mid + 1
            elif nums[mid] > target:
                r = mid - 1
            else:
                index = mid
                break
        return index