num1^num2得和,没有加进位
num1&num2得进位
再相加,循环至进位为0
class Solution {
public:
int Add(int num1, int num2)
{
while(num2)
{
int sum = num1^num2;
int pre = (num1&num2)<<1;
num1 = sum;
num2 = pre;
}
return num1;
}
};