Tag: follow

The previous question was not clear enough so I will try to clarify it more in this follow-up question.
I tried the multiple pointers technique to solve the problem that find pair of values that sums up to a target value.

We are assuming that:

• the array is already sorted.
• we are working with a static array of size 16 (testing purpose only).
• we are not working with actual pointers; because we don’t need them in this case (I think), I named the question on the algorithm’s
  name only.

    #include <iostream> 
    #include <vector> 
    using namespace std;
    
        struct result
         {
             int num1;
             int num2;
             result() {}
        
             result(int num1, int num2)
                 : num1{ num1 }, num2{ num2 } {}
         };
        
         vector<result> mult_pt(int arr(), int target)
         {
             int p1 = 0;
             int p2 = 15;
             bool flag = false;
             vector<result> res;
             while (p1 <= p2)
             {
                 if (arr(p1) + arr(p2) == target)
                 {
        
                     for (int k = 0; k < res.size() - 1; k++)
                     {
                         if (res.size() == 0)
                             res.push_back(result(arr(p1), arr(p2)));
                         else if (res(k).num1 != arr(p1) && res(k).num2 != arr(p2))
                         { 
                             flag = false;
                         }
                         else flag = true;
                     }
                     if(flag) res.push_back(result(arr(p1), arr(p2)));
                     p1++;
                 }
                 else if (arr(p1) + arr(p2) < target)
                 {
                     p1++;
                     continue;
                 }
                 else if (arr(p1) + arr(p2) > target)
                 {
                     p2--;
                     for (int i = p1; i >=0; i--)
                     {
                         if (arr(i) + arr(p2) == target)
                         {
                             res.push_back(result(arr(p1), arr(p2)));
                         }
                         else if (arr(i) + arr(p2) > target)
                         {
                             continue;
                         }
                         else break;
                     }
                 }
             }
             return res;
         }

int main ()
{
  int array(16) = { 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
  vector <result> res = mult_pt(array, 19);
  for (int j = 0; j < res.size(); j++)
    {
        cout << "( " << res(j).num1 << " , " << res(j).num2 << " )" << endl;
    }
  return 0;
}

The output should be like:

( 4 , 15 )
( 5 , 14 )
( 6 , 13 )
( 7 , 12 )
( 8 , 11 )
( 9 , 10 )
( 10 , 9 )

You can check the previous post here.