Challenge: Calculate the Number of Nodes in a Given Graph Level

Problem Statement

Implement a function that returns the number of nodes at a given level of an undirected graph in C++.

Try modifying the Breadth-First Traversal algorithm to achieve this goal.

Input

An undirected graph represented as an adjacency list, a starting vertex, and the level whose number of nodes we need to find.

Output

The number of nodes returned as a simple integer.

Sample Input

Graph:

graph {0 - 1
       0 - 2
       1 - 3
       2 - 3
       3 - 5
       2 - 4
}

Level: 1

Sample Output

1