Leetcode Guess Number Higher or Lower

题意：猜数字游戏。

思路：二分查找。

// Forward declaration of guess API.// @param num, your guess// @return -1 if my number is lower, 1 if my number is higher, otherwise return 0int guess(int num);class Solution {public:    int guessNumber(int n) {        if(guess(n) == 0) return n;        if(guess(1) == 0) return 1;                int low = 1;        int high = n;        while(low != high) {            int mid = low + (high - low) / 2;            if(guess(mid) == 0) return mid;            if(guess(mid) == -1) high = mid;            if(guess(mid) == 1) low = mid + 1;        }        return 0;    }};