How to Check Bipartite Graph Using BFS in Python
In this tutorial, we will learn "How to Check if a Graph is Bipartite using BFS in Python". The main objective is to understand and implement a method for checking whether a graph is bipartite using Breadth-First Search (BFS). This guide will walk you step by step through the process, making it easier to follow and apply. By the end of this tutorial, you will have a solid understanding of how BFS works in Python for this problem, helping you strengthen your problem-solving abilities and improve your overall coding skills in data structure implementation.
This topic is straightforward and easy to understand. By following the instructions provided, you will be able to complete it with ease. The program will guide you step by step through the process of implementing a bipartite graph check using BFS. So, let’s dive into the coding process and start implementing the solution to gain a deeper understanding of checking a bipartite graph using BFS in Python.
Getting Started:
First you will have to download & install the Python IDLE's, here's the link for the Integrated Development And Learning Environment for Python https://www.python.org/downloads/.
Creating Main Function
This is the main function of the application. The following code will display a simple GUI in terminal console that will display program. To do this, simply copy and paste these blocks of code into the IDLE text editor.- from collections import deque
- def is_bipartite(graph, start):
- color = {}
- queue = deque([start])
- color[start] = 0 # Assign first color
- while queue:
- node = queue.popleft()
- for neighbor in graph[node]:
- if neighbor not in color:
- color[neighbor] = 1 - color[node] # Alternate color
- queue.append(neighbor)
- elif color[neighbor] == color[node]:
- return False # Same color conflict → not bipartite
- return True
- # MAIN PROGRAM
- while True:
- print("\n========== Check Bipartite Graph Using BFS ==========\n")
- graph = {}
- # Input number of vertices
- try:
- n = int(input("Enter number of vertices: "))
- except ValueError:
- print("Invalid input.")
- continue
- # Input adjacency list
- print("\nEnter adjacency list (space-separated neighbors):")
- for i in range(n):
- try:
- neighbors = list(map(int, input(f"Vertex {i}: ").split()))
- graph[i] = neighbors
- except ValueError:
- print("Invalid input.")
- break
- # Check bipartite
- result = True
- visited = set()
- for node in graph:
- if node not in visited:
- if not is_bipartite(graph, node):
- result = False
- break
- visited.update(graph.keys())
- # Output result
- if result:
- print("\nGraph is Bipartite ✅")
- else:
- print("\nGraph is NOT Bipartite ❌")
- # Try Again Option
- opt = input("\nDo you want to try again? (yes/no): ").strip().lower()
- if opt == "no":
- print("Exiting program...")
- break
- elif opt != "yes":
- print("Invalid choice. Exiting program...")
- break
This Python program checks whether a graph is bipartite using Breadth-First Search (BFS). It defines an `is_bipartite` function that uses a queue to traverse the graph and assigns alternating colors to adjacent vertices, ensuring no two connected vertices share the same color. The user inputs the number of vertices and their adjacency lists, and the program evaluates each connected component of the graph. If a conflict in coloring is found, the graph is not bipartite; otherwise, it is bipartite. The program runs interactively, allowing users to test multiple graphs until they choose to exit.
Output:
There you have it we successfully created How to Check Bipartite Graph Using BFS in Python. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!
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