How To Find the Intersection of Two Multimaps in C++?

In C++, finding the intersection of two multimaps consists of identifying the common elements that are shared between both collections, containing key-value pairs. In this article, we will learn how to find the intersection of two multimaps in C++ STL.

Example:

Input:
multimap1 = {1, "Java"}, {2, "Python"}, {3, "C++"}, {4, "JavaScript"}
mutlimap2 = {2, "Python"}, {4, "JavaScript"}, {5, "TypeScript"}
Output:
Intersection:
{2: Python}
{4: JavaScript}

Intersection of Two Multimaps With Common Values in C++

To find the intersection between two multimaps in C++ STL, we have to iterate through each element using a loop in the first multimap and search for the corresponding elements in the second multimap. If the matching element is found then it is inserted into the result multimap.

C++ Program to Find the Intersection of Two Multimaps

The below program demonstrates how we can find the intersection between two multimaps in C++.

Intersection MultiMap:
2: Python
4: JavaScript

Time Complexity: O(min(N, M), where N is the number of elements in multi1 and M is the number of elements in multi2.
Auxilliary Space: O(K), where K is the number of common elements.