- 704 二分查找
第一遍写的时候忘了写返回, return helper(mid+1, end) 那里一定记得取回返回值
class Solution:
def search(self, nums, target): #: List[int], target: int) -> int:
if not nums: return -1
def helper(start, end):
if start > end: return -1
mid = (start+end) // 2
if nums[mid] == target: return mid
elif nums[mid] < target:
return helper(mid+1, end)
else: # nums[mid] > target:
return helper(start, mid-1)
return helper(0, len(nums)-1)