题目描述：
We are playing the Guess Game. The game is as follows:
I pick a number from 1 to n. You have to guess which number I picked.
Every time you guess wrong, I‘ll tell you whether the number is higher or lower.
You call a pre-defined API guess(int num) which returns 3 possible results (-1, 1, or 0):
-1 : My number is lower 1 : My number is higher 0 : Congrats! You got it!
Example:
n = 10, I pick 6. Return 6.
解题思路：
二分查找法的变体
代码如下：
# The guess API is already defined for you.
# @param num, your guess
# @return -1 if my number is lower, 1 if my number is higher, otherwise return 0
# def guess(num):
class Solution(object):
def guessNumber(self, n):
"""
:type n: int
:rtype: int
"""
left, right = 1, n
while(left <= right):
mid = (left + right) / 2
res = guess(mid)
if res == 0:
return mid
elif res == -1:
right = mid -1
elif res == 1:
left = mid + 1
return -1
Python [Leetcode 374]Guess Number Higher or Lower
原文：http://www.cnblogs.com/zihaowang/p/5721933.html