374.猜数字大小

😂二分查找

int guess(int num);

class Solution {
public:
    int guessNumber(int n) {
        int lo = 1,
        hi = n,
        mi, test;
        while(lo <= hi) {
            mi = lo + (hi - lo) / 2;
            test = guess(mi);
            if(test < 0) {
                hi = mi - 1;
            } else if (test > 0) {
                lo = mi + 1;
            } else {
                return mi;
            }
        }
        return -1;
    }
};

Accepted

25/25 cases passed (4 ms)

Your runtime beats 59.61 % of cpp submissions

Your memory usage beats 5.55 % of cpp submissions (8.3 MB)