# 374. Guess Number Higher or Lower

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.
``````

``````int guess(int num);

class Solution {
public:
int guessNumber(int n) {
if (guess(n) == 0) return n;
int left = 1, right = n;
while (left < right) {
int mid = left + (right - left) / 2, t = guess(mid);
if (t == 0) return mid;
if (t == 1) left = mid + 1;
else right = mid;
}
return left;
}
};
``````

Github 同步地址：

https://github.com/grandyang/leetcode/issues/374

Find K Closest Elements

https://leetcode.com/problems/guess-number-higher-or-lower/

https://leetcode.com/problems/guess-number-higher-or-lower/discuss/84664/0ms-c%2B%2B-binary-search

LeetCode All in One 题目讲解汇总(持续更新中…)

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