*LeetCode 29. Divide Two Integers

https://leetcode.com/problems/divide-two-integers/

非常想知道有什么不用long long就可以A掉的方法，似乎没有

我写的： 模拟除法，学过汇编应该很容易理解

需要特殊判断的是：

如果被除数是-2147483648

const int MAX_INT = 2147483647;
const int MIN_INT = -2147483648;

class Solution {
public:
    int divide(int dividend, int divisor) {

        long long div = dividend, dis = divisor;
        int flag = ((div > 0 && dis > 0) || (div < 0 && dis < 0)) ? 1 : -1;
        if(div<0) div = -div;
        if(dis<0) dis = -dis;
        if(dis == 0) return MAX_INT;
        if(dividend == MIN_INT) {
            if(divisor == 1) return dividend;
            if(divisor == -1) return MAX_INT;
        }
        long long ret = 0;

        for(int i=31; i>=0; i--) {
            long long tmp = (long long)(dis<<i);
            if(div >= tmp) {
                ret += (1<<i);
                div -= tmp;
                //cout << "tmp=" << tmp << "  div=" << div << endl;
            }
        }
        ret *= flag;
        cout << ret << "  ret" << endl;
        if(ret >=MAX_INT || ret < MIN_INT) return MAX_INT;
        return ret;
    }
};