**Solution**

**Guess Number Higher or Lower** https://leetcode.com/problems/guess-number-higher-or-lower/

**Binary Search**

- low to high is 1 to N. Apply standard binary search.

```
class Solution(object):
def guessNumber(self, n):
"""
:type n: int
:rtype: int
"""
low = 1
high = n
while low <= high:
mid = low + (high-low)//2
ans = guess(mid)
if ans == 0:
return mid
elif ans == -1:
high = mid - 1
else:
low = mid + 1
```