Non_Weighted_Graph.py

class Graph:
  
  def __init__(self, directed = False):
    
    self.graph = {}
    self.directed = directed
    
  def add_node(self, node):
    
    if node not in self.graph:
      self.graph[node] = []
      
  def add_edge(self, node1, node2):
    
    if node1 in self.graph and node2 in self.graph:
      
      self.graph[node1].append(node2)
      
      if not self.directed:
        self.graph[node2].append(node1)
        
  def remove_node(self, node):
    
    if node in self.graph:
      
      for neighbor in self.graph[node]:
        self.graph[neighbor].remove(node)
        
      del self.graph[node]
      
  def remove_edge(self, node1, node2):
    
    if node1 in self.graph and node2 in self.graph:
      
      self.graph[node1].remove(node2)
      
      if not self.directed:
        self.grpah[node2].remove(node1)
        
  def BFS(self, start):
    
    visited = set()
    queue = [start]
    result = []
    
    while queue:
      
      node = queue.pop(0)
      
      if node not in visited:
        visited.add(node)
        result.append(node)
        
        for neighbor in self.graph[node]:
          if neighbor not in visited:
            queue.append(neighbor)
          
    return result
  
  def DFS(self, start):
    
    visited = set()
    stack = [start]
    result = []
    
    while stack:
      
      node = stack.pop()
      
      if node not in visited:
        visited.add(node)
        result.append(node)
        
        for neighbor in reversed(self.graph[node]): 
          if neighbor not in visited:
            stack.append(neighbor)
          
    return result   
        
  def display(self):
    
    for key, value in self.graph.items():
      print(f"{key}: {value}")
      

if __name__ == "__main__":
  
  graph = Graph()
  
  graph.add_node('A')
  graph.add_node('B')
  graph.add_node('C')
  graph.add_node('D')
  
  graph.add_edge('A', 'B')
  graph.add_edge('B', 'C')
  graph.add_edge('A', 'D')
  graph.add_edge('C', 'D')
  
  graph.display()
  
  print(graph.BFS('A'))
  print(graph.DFS('A'))