We are playing the Guess Game. The game is as follows:
I pick a number from
n. You have to guess which number I picked.
Every time you guess wrong, I will tell you whether the number I picked is higher or lower than your guess.
You call a pre-defined API
int guess(int num), which returns 3 possible results:
-1: The number I picked is lower than your guess (i.e.
pick < num).
1: The number I picked is higher than your guess (i.e.
pick > num).
0: The number I picked is equal to your guess (i.e.
pick == num).
Return the number that I picked.
Input: n = 10, pick = 6 Output: 6
Input: n = 1, pick = 1 Output: 1
Input: n = 2, pick = 1 Output: 1
Input: n = 2, pick = 2 Output: 2
1 <= n <= 231 - 1
1 <= pick <= n
Do a binary search to find the pick.
# 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: int) -> int: class Solution: def guessNumber(self, n: int) -> int: start = 1 end = n while start + 1 < end: mid = start + (end - start) // 2 if guess(mid) == 0: return mid elif guess(mid) == -1: end = mid else: start = mid if guess(end) == 0: return end if guess(start) == 0: return start
- Time Complexity: O(log(N)).
- Space Complexity: O(1).