374. Guess Number Higher or Lower

https://leetcode.com/problems/guess-number-higher-or-lower/description/
Solution 1. Recursion.
    int guessing(int lo, int hi) {
        int mi = (hi - lo)/2 + lo;
        int c = guess(mi);
        if(c==0) return mi;
        else if(c==1) return guessing(mi+1, hi);
        else return guessing(lo, mi-1);
    }
    int guessNumber(int n) {
        return guessing(1, n);
    }
Solution 2. Iteration.
    int guessNumber(int n) {
        int mi, re, hi = n, lo = 1;
        while(true) {
            mi = (hi - lo)/2 + lo;
            re = guess(mi);
            if(re == 0) return mi;
            else if(re == 1) lo = mi + 1;
            else hi = mi - 1;
        }
    }