371. 两整数之和

class Solution {
public:
    int getSum(int a, int b) {
        int ans[100] = {0};
        int flag_A = 1;
        int flag_B = 1;
        if(a < 0)
        {
            flag_A = -1;
            a = -a;
        }
        if(b < 0)
        {
            flag_B = -1;
            b = -b;
        }
        //1.先把数字拆分成数组，方便每个位数计算
        vector<int> V_a;
        vector<int> V_b;
        while(a != 0)
        {
            V_a.push_back(a%10);
            a = a / 10;
        }
        while(b != 0)
        {
            V_b.push_back(b%10);
            b = b / 10;
        }
        //2.让各个数字进行累加
        int i;
        for( i = 0;i < V_a.size() || i < V_b.size();i++)
        {
            if(i < V_a.size() && i < V_b.size())
            {
                ans[i] = flag_A*V_a[i] + flag_B*V_b[i];
            }
            else if(i < V_a.size())
            {
                ans[i] = flag_A*V_a[i];
            }else if(i < V_b.size())
            {
                ans[i] = flag_B*V_b[i];
            }
        }
        //3.然后再把累加数字进位
        int Ans = 0;
        int carry = 0;
        for(int j = 0;j < i;j++)
        {
            ans[j] += carry;
            if(ans[j] < 0 && !(flag_A == -1 && flag_B == -1))
            {
                carry--;
                ans[j] += 10;
            }
            else{
                carry = ans[j] / 10;
            }
            ans[j] = ans[j] % 10;
        }
        //
        if(carry != 0)
        {
            ans[i] = carry;
            i++;
        }
        //计算结果
        for(int j = i-1;j >= 0;j--)
        {
            Ans = Ans*10 + ans[j];
        }
        return Ans;

    }
};