python实现 LeetCode34——Search for a Range

二分法找到target的位置，再判断前后的位置

class Solution(object):
    def searchRange(self, nums, target):
        start=0
        end=len(nums)-1
        while start<=end and start>=0 and end<=len(nums)-1:
            mid=(start+end)/2
            if nums[mid]==target:
                start = mid
                end =  mid
                while start>0 and nums[start - 1] == nums[start]:
                    start = start - 1
                while endtarget:
                    end=mid-1
                else:
                    start=start+1
        return [-1,-1]