Remove a Specific Pair From a Multimap in C++
To remove a specific pair from a std::multimap, we can use the std::multimap::equal_range function to get a range of iterators representing all occurrences of the key, and then use the std::multimap::erase function to remove each occurrence of the key-value pair.
C++ Program to Remove a Specific Pair From a Multimap
C++
// C++ program to illustrate how to remove the specific key // value pair from a multimap #include <iostream> #include <map> using namespace std; int main() { // Creating a multimap multimap< int , string> myMultimap = { { 1, "one" }, { 2, "two" }, { 2, "two" }, { 3, "three" } }; // Key-value pair to remove int keyToRemove = 2; string valueToRemove = "two" ; // Getting the range of the key auto range = myMultimap.equal_range(keyToRemove); // Removing all occurrences of the key-value pair for ( auto it = range.first; it != range.second;) { if (it->second == valueToRemove) { it = myMultimap.erase(it); } else { ++it; } } // Printing the multimap after removing the key-value // pair cout << "Multimap after removing the key-value pair:" << endl; for ( const auto & pair : myMultimap) { cout << pair.first << " => " << pair.second << endl; } return 0; } |
Multimap after removing the key-value pair: 1 => one 3 => three
Time complexity: O(M *log N), where M is the count of elements associated with a particular key and N is the total number of elements in the multimap.
Space Complexity: O(N)
How to Remove a Specific Pair From a Multimap in C++?
In C++, a multimap is a container that can store multiple key-value pairs, where each key can be associated with multiple values. In this article, we will learn how to remove all occurrences of a specific key-value pair from a multimap in C++.
Example
Input: myMultimap = {{1, “one”}, {2, “two”}, {2, “two”}, {3, “three”}}; Key-Value Pair to Remove = {2, “two”}; Output: myMultimap = {{1, “one”}, {3, “three”}};