學習筆記 | 在排序數組中查找元素的第一個和最後一個位置

class Solution(object):
    def searchRange(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        def findlow(nums,target,low,high):
            
            while low <= high:
                mid = low + (high-low)//2
                if nums[mid] == target and (mid == 0 or nums[mid-1] < nums[mid]):
                    return mid
                if nums[mid] >= target:
                    high = mid-1
                else:
                    low = mid+1
            
            if low > high:
                return -1
            
        
        def findhigh(nums,target,low,high):
            while low <= high:
                mid = low + (high-low)//2
                if nums[mid] == target and (mid == len(nums)-1 or nums[mid+1] > nums[mid]):
                    return mid

                if nums[mid] > target:
                    high = mid-1
                else:
                    low = mid+1
            
            if low > high:
                return -1
        
        ans = []
        low = findlow(nums,target,0,len(nums)-1)
        high = findhigh(nums,target,0,len(nums)-1)
        ans.append(low)
        ans.append(high)
        return ans