题目

WeChat911ebb8245209624507d2e593ac9e44b.png

要点

  • Binary Search

代码

  1. class Solution(object):
  2.     def firstBadVersion(self, n):
  3.         """
  4.         :type n: int
  5.         :rtype: int
  6.         """
  8.         l = 1
  9.         while (l <= n):
  10.             target =  (l + n) // 2
  11.             if(isBadVersion(target) == True):
  12.                 if(isBadVersion(target-1) == False):
  13.                     return target
  14.                 else:
  15.                     n = target - 1
  16.             else:
  17.                 l = target + 1 
  18.         return -1

分析

二分查找(binary search)是算法中必须掌握的基础算法之一。此题与二分法无异