力扣34. 在排序数组中查找元素的第一个和最后一个位置

 1 class Solution:
 2     def searchRange(self, nums: List[int], target: int) -> List[int]:
 3         ans,lens = [-1,-1],len(nums)
 4         left,right,flag = 0,lens - 1,True
 5         while left <= right and flag:
 6             mid = left + (right - left) // 2
 7             if nums[mid] == target:
 8                 i = j = mid
 9                 while i >= 0 or j < lens:
10                     if i >= 0 and nums[i] == target: 
11                         ans[0] = i
12                     if j < lens and nums[j] == target:
13                         ans[1] = j
14                     i -= 1
15                     j += 1
16                 flag = False
17             elif nums[mid] > target:
18                 right = mid - 1
19             else:left = mid + 1
20         return ans
21