您的位置:首页 > 产品设计 > UI/UE

[leetcode] 374. Guess Number Higher or Lower 解题报告

2016-07-16 03:13 701 查看
题目链接:https://leetcode.com/problems/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.


思路: 只是二分就行, 需要注意溢出问题.

代码如下:

// Forward declaration of guess API.
// @param num, your guess
// @return -1 if my number is lower, 1 if my number is higher, otherwise return 0
int guess(int num);

class Solution {
public:
int guessNumber(int n) {
int low = 1, high = n;
while(low <= high)
{
int mid = (high-low)/2+low, val = guess(mid);
if(val == 0) return mid;
else val==-1?high=mid-1:low=mid+1;
}
return -1;
}
};
内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签:  leetcode binary search