Graph definition as class

graph_definition.py

class GraphNode:
    
    def __init__(self, value, neighbors):
        """Initialize graph node
        
        Parameters
        ----------
        
        name: str
            node identifier
        children: list
            list of child nodes
        """
        self.value = value
        self.neighbors = neighbors
        

class Graph:
    
    def __init__(self, vert_dict):
        """
        
        Parameters
        ----------
        
        vert_dict: dictionary
            dictionart containing node ids as keys and node neighbors as values
        """
        self.nodes = {}
        for v in vert_dict.keys():
            self.nodes[v] = GraphNode(v, vert_dict[v])

            
# Actually, we don't need a special structure to store it!
g = {0: [1, 2, 3], 1: [0, 2], 2: [0, 1], 3: [0]}

print(Graph(g))
# Another way: as an adjacency matrix
g = [[0, 1, 1, 1], [1, 0, 1, 0], [1, 1, 0, 0], [1, 0, 0, 0]]

# DFS and BFS usage
# DFS -> if we need to traverse the graph completely. E.g., if we need to check if there are cycles