題目描述:
統計一個數字在排序數組中出現的次數。
思路:
利用二分法尋找左右端點。
代碼:
代碼
# -*- coding:utf-8 -*-
class Solution:
def GetNumberOfK(self, data, k):
# write code here
if not data:
return 0
low = 0
high = len(data) - 1
cnt = 0
end = len(data) - 1
while low <= high:
medium = (low + high) / 2
if data[medium] == k:
# print "medium: ", medium
# 這個數字前面後面都可能存在我們要找的數
while medium >= 0 and data[medium] == k:
medium -= 1
medium += 1
# print "left: ", medium
while medium <= end and data[medium] == k:
medium += 1
cnt += 1
return cnt
elif data[medium] < k:
low = medium + 1
else:
high = medium - 1
return cnt