Guess Number Higher or Lower

unlocked question, 不貼截圖了

EST 7/13/2016, 1:14AM. Beijing time 7/13/2016, 1:14PM. 截至目前Leetcode最新的一道題 I'm loling, 這還是我第一次做剛剛發(fā)出來的題
現(xiàn)在題越來越多，大量重復題，這道題是很典型的binary search
用leetcode給出的函數(shù): int guess(int num)判斷現(xiàn)在的數(shù)字是大了還是小了，binary search小了就往右，大了就往左

// 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(0), high(n);
        while (low <= high) {
            int mid = low + (high - low) / 2;
            int d = guess(mid);
            if (d == 0) return mid;
            else if (d == 1) low = mid + 1;
            else high = mid - 1;
        }
        return high;
    }
};