# LeetCode : 0371. Sum of Two Integers (bits)
###### tags:`leetcode`

#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <unordered_map>
#include <bitset>
using std::vector;
using std::unordered_map;
using namespace std;

class BaseVectorPrint {
    public:
        void BasePrint00(vector<int>& num) {
            for (size_t i = 0; i < num.size(); ++i) {
                cout << "[" <<num.at(i) << "]" << "; ";
            }
            cout << endl;
        }

        void BasePrint01(vector<int>& num) {
            for (size_t i = 0; i < num.size(); ++i) {
                cout << num[i] << "; ";
            }
            cout << endl;
        }

        void BasePrint02(vector<int>& num) {
            for (const auto &item : num) {
                cout << item << "; ";
            }
            cout << endl;
        }
        
        void TwoDimensionalPrint(vector<vector<int>> &num){
            for (int i = 0; i < num.size(); i++)
            {
                for (int j = 0; j < num[i].size(); j++)
                {
                    cout << "[" << num[i][j] << "]";
                }
                cout << endl;
            }
        }
};

string toBinary(int n)
{
    string r;
    while (n != 0){
        r += ( n % 2 == 0 ? "0" : "1" );
        n /= 2;
    }
    return r;
}

class Solution01 {
public:
    int getSum(int a, int b) {
        if (a == 0) return b;
        if (b == 0) return a;
        int intTobit = 0;
        while(b != 0){
            unsigned carry=a&b; // check math carry value.
            intTobit = carry;
            bitset<32> bs1(toBinary(intTobit));
            cout << "carry = " << intTobit << endl;
            a=a^b;  // sum a and b , without caryy value. if carry value add it , will clear carry bit until 0,
            b=carry<<1; //shift carry value until add it.
        }
        return a;       
    }
//time complexity O(1)
//space complexity O(1)
};

class Solution02 {
public:
    int getSum(int a, int b) {
        long mask = 0xFFFFFFFF;
        
        while (b != 0) {
            int answer = (a ^ b) & mask;
            int carry = ((a & b) & mask) << 1;
            a = answer;
            b = carry;
        }
         
        return a < INT_MAX ? a : ~(a ^ mask);
    }
//time complexity O(1)
//space complexity O(1)
};

int main(void)
{
    BaseVectorPrint printVector;
    Solution01 runfunc;

    vector<int> test01 = {  4,  5,  1,  8,  2 };
    vector<int> test02 = {  1,  2,  3,  4 };
    vector<int> test03 = { -1,  1,  0, -3,  3 };
    vector<int> ans ;

    int intans;
    int a1 = 1;
    int b1 = 2;
    int a2 = 2;
    int b2 = 3;
    int a3 = 15;
    int b3 = 2;

    intans = runfunc.getSum(a3,b3);
    //printVector.BasePrint00(ans);

    printf("ans = %d\n",intans);
    printf("test\n");
    system("pause");
}