分析
代码
1 class Solution
2 {
3 public:
4 int divide(int x, int y)
5 {
6 typedef long long ll;
7 vector<ll> exp;
8 bool is_minus = false;
9
10 if ((x > 0 && y < 0 )|| (x < 0 && y > 0))
11 is_minus = true;
12
13 ll a = abs((ll)x), b = abs((ll)y);
14 for (ll i = b; i <= a; i = i + i)
15 exp.push_back(i);
16
17 ll res = 0;
18 for (int i = exp.size() - 1; i >= 0; i--)
19 {
20 if ( a >= exp[i])
21 {
22 a -= exp[i];
23 res += 1ll << i; //2的i次方 ,注意31次方移位会溢出所以转ll
24
25 }
26 }
27
28 if (is_minus)
29 res = -res;
30
31 if (res > INT_MAX || res < INT_MIN)
32 res = INT_MAX;
33 return res;
34 }
35 };
