In C++, the Standard Template Library (STL) provides a container called deque that allows efficient insertion and deletion operations at both ends of the container. A map is an associative container that stores elements in key-value pairs.In this article, we will learn how to create a deque of maps in C++.

Example

Input:
myMap1: {1: "C++", 2: "Python"}
myMap2: {1: "Java", 3: "Javascript"}

Output:
myDeque: [ {1: "C++", 2: "Python"},
            {1: "Java", 3: "Javascript"} ]

Create a Deque of Maps in C++

To create a std::deque of std::maps in C++, we have to define the type of the deque element as std::map in the deque declaration as shown in the below syntax:

Syntax to Create a Deque of Maps in C++

deque<map<KeyType, ValueType>> deque_Name;

C++ Program to Create a Deque of Maps

The following program illustrates how to create a deque of maps in C++:

// C++ Program to illustrate how to create a deque of maps
#include <deque>
#include <iostream>
#include <map>
using namespace std;

int main()
{
    // Initialize a deque of maps
    deque<map<int, string> > dq;

    // Initialize maps with few entries
    map<int, string> mp1;
    mp1[1] = "C++";
    mp1[2] = "Java";

    map<int, string> mp2;
    mp2[1] = "JavaScript";
    mp2[2] = "Python";

    // Insert the maps to the deque
    dq.push_back(mp1);
    dq.push_back(mp2);

    // Print the deque of maps
    cout << "Deque Elements: " << endl;
    int i = 1;
    for (auto it = dq.begin(); it != dq.end(); ++it) {
        cout << "Map" << i << " { ";
        for (auto p : *it) {
            cout << "{" << p.first << ", " << p.second
                 << "} ";
        }
        i++;
        cout << " }" << endl;
    }
    return 0;
}

Deque Elements: 
Map1 { {1, C++} {2, Java}  }
Map2 { {1, JavaScript} {2, Python}  }

Time Complexity: O(N*M)where N is the number of elements in the map.
Auxiliary Space: O(N*M), where M is the average number of key-value pairs in map.