CODEWITHSUNDEEP
c++oop
Kristen93minecraft
Kristen93minecraft

Reputation: 11

Easiest way to combine 2 double array sets into one finding their unions and intersections

I've been trying to get this done but i'm stuck right now. Can anyone please recommend the easiest way to get it done? Thank you

c[i] = a[i] + b[i];

// The snippet of code I have above works fine with operator: + - / * 
// a[i] = { 1, 8, 13, 15 }
// b[i] = { 3, 8, 13, 20 }
// then  c[i] = { 4, 16, 26, 35 }

// But how do i find the union and intersection of both arrays?
// I want the results to look like:
// union = {1,3,8,13,15,20}
// intersection = {8,13}

Upvotes: 1

Views: 66

Answers (2)

dorKKnight
dorKKnight

Reputation: 119

since you asked for easiest way. you can put the elements of the arrays into 2 std::set 

std::set<T> set1(begin(array1), end(array1));
std::set<T> set2(begin(array2), end(array2));

Then use std::set_union and std::set_intersection in 2 new std::set. Please take a look at the way its done in these links set union and set intersection Thus STL takes care of most of the logic and containers.

Upvotes: 2

Deenadhayalan Manoharan
Deenadhayalan Manoharan

Reputation: 5444

Try this..

//Unioin of 2 array

#include<stdio.h>

int printUnion(int arr1[], int arr2[], int m, int n)
{
  int i = 0, j = 0;
  while(i < m && j < n)
  {
    if(arr1[i] < arr2[j])
      printf(" %d ", arr1[i++]);
    else if(arr2[j] < arr1[i])
      printf(" %d ", arr2[j++]);
    else
    {
      printf(" %d ", arr2[j++]);
      i++;
    }
  }


  while(i < m)
   printf(" %d ", arr1[i++]);
  while(j < n)
   printf(" %d ", arr2[j++]);
}


int main()
{
  int arr1[] = {1, 8, 13, 15};
  int arr2[] = {3, 8, 13, 20};
  int m = sizeof(arr1)/sizeof(arr1[0]);
  int n = sizeof(arr2)/sizeof(arr2[0]);
  printUnion(arr1, arr2, m, n);
  getchar();
  return 0;
}


//Intersection of two array

#include<stdio.h>

int printIntersection(int arr1[], int arr2[], int m, int n)
{
  int i = 0, j = 0;
  while(i < m && j < n)
  {
    if(arr1[i] < arr2[j])
      i++;
    else if(arr2[j] < arr1[i])
      j++;
    else /* if arr1[i] == arr2[j] */
    {
      printf(" %d ", arr2[j++]);
      i++;
    }
  }
}


int main()
{
  int arr1[] = {1, 8, 13, 15};
  int arr2[] = {3, 8, 13, 20};
  int m = sizeof(arr1)/sizeof(arr1[0]);
  int n = sizeof(arr2)/sizeof(arr2[0]);
  printIntersection(arr1, arr2, m, n);
  getchar();
  return 0;
}

Upvotes: 0

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