題目：

統計一個數字在排序陣列中出現的次數。例如輸入排序陣列[1, 2, 3, 3, 3, 3, 4, 5]和數字3，由於3在這個陣列中出現了4次，因此輸出4。
樣例
輸入：[1, 2, 3, 3, 3, 3, 4, 5] , 3
輸出：4

解答：

class Solution(object):
    def getNumberOfK(self, nums, k):
        """
        :type nums: list[int]
        :type k: int
        :rtype: int
        """
        number =
 
 0
        s = self.getFirstK(nums, k, 0, len(nums) - 1)
        e = self.getLastK(nums, k, 0, len(nums) - 1)
        if s >= 0 and e >= 0:
            number = e - s + 1
        return number
    
    def getFirstK(self, nums, k, start, end):
        if start > end:
            return -1
        mid =
 
 int((start + end)/2)
        if nums[mid] == k:
            if mid > 0 and nums[mid - 1] != k or mid == 0:
                return mid
            else:
                end = mid - 1
        else:
            if nums[mid] > k:
                end = mid - 1
            else:
                start =
 
 mid + 1
        return self.getFirstK(nums, k, start, end)
    
    def getLastK(self, nums, k, start, end):
        if start > end:
            return -1
        mid = int((start + end)/2)
        if nums[mid] == k:
            if mid < end and nums[mid + 1] != k or mid == end:
                return mid
            else:
                start = mid + 1
        else:
            if nums[mid] > k:
                end = mid - 1
            else:
                start = mid + 1
        return self.getLastK(nums, k, start, end)