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Graphs in Python
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‎graphs/README.md

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# Data Structures and Algorithms (DSA) In Python
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This repository is for the students of book [Data Structures and Algorithms In Python](http://coursegalaxy.com/) and online courses available on CourseGalaxy. It contains the source code of all the programs used in the book and courses.
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### About the DSA Masterclass Courses
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* Thoroughly detailed courses with complete working programs
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* Contains lots of animations to help you visualize the concepts
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* Includes various Data Structures and Algorithms
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* Builds a solid foundation in Data Structures and Algorithms
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* Prepares you for coding interviews
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* Lifetime Access
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### DSA Masterclass Courses on [CourseGalaxy](http://coursegalaxy.com/)
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[![data-structures-algorithms-python](https://user-images.githubusercontent.com/96913690/200234827-86aec10a-bfab-4371-91fc-e2be855ff1ff.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-python?coupon_code=GITHUB75PER)
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[![data-structures-algorithms-java](https://user-images.githubusercontent.com/96913690/200234744-14a5ed97-085f-44f3-9298-979c2053c580.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-java?coupon_code=GITHUB75PER)
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[![data-structures-algorithms-c](https://user-images.githubusercontent.com/96913690/200234592-25d33957-0e9e-4cc0-b324-2a73325aca85.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-c?coupon_code=GITHUB75PER)
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[![data-structures-algorithms-csharp](https://user-images.githubusercontent.com/96913690/200234905-67b85dfd-20c4-4f4b-afd2-e10d3568fff8.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-csharp?coupon_code=GITHUB75PER)
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## Copyright
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© Copyright Suresh Kumar Srivastava : All rights reserved.
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Not to be used for commercial purposes.

‎graphs/adjacency-list/directed_graph_list.py

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# Copyright (C) Suresh Kumar Srivastava - All Rights Reserved
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# DSA Masterclass courses are available on CourseGalaxy.com
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# directed_graph_list.py : Program for directed graph using adjacency list.
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class VertexNode:
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def __init__(self, name):
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self.name = name
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self.next_vertex = None
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self.first_edge = None
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class EdgeNode:
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def __init__(self, v):
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self.end_vertex = v
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self.next_edge = None
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class DirectedGraphList:
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def __init__(self):
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self._nvertices = 0
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self._nedges = 0
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self._start = None
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def insert_vertex(self, vertex_name):
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ptr = None
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temp = None
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vertex_found = False
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ptr = self._start
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if ptr == None:
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temp = VertexNode(vertex_name)
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self._start = temp
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self._nvertices += 1
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else:
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while ptr.next_vertex != None:
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if ptr.name == vertex_name:
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vertex_found = True
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break
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ptr = ptr.next_vertex
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if vertex_found or ptr.name==vertex_name:
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print("Vertex already present")
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else:
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temp = VertexNode(vertex_name)
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ptr.next_vertex = temp
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self._nvertices += 1
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def _find_vertex(self, vertex_name):
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ptr = self._start
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while ptr != None:
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if ptr.name == vertex_name:
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break
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ptr = ptr.next_vertex
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return ptr
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def insert_edge(self, source, destination):
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u = None
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v = None
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edge_ptr = None
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temp = None
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edge_found = False
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if source == destination:
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print("Invalid Edge : source and destination vertices are same")
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else:
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u = self._find_vertex(source)
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v = self._find_vertex(destination)
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if u == None:
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print("Source vertex not present, first insert vertex " + source)
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elif v == None:
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print("Destination vertex not present, first insert vertex " + destination)
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else:
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if u.first_edge == None:
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temp = EdgeNode(v)
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u.first_edge = temp
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self._nedges += 1
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else:
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edge_ptr = u.first_edge
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while edge_ptr.next_edge != None:
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if edge_ptr.end_vertex.name == v.name:
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edge_found = True
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break
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edge_ptr = edge_ptr.next_edge
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if edge_found or edge_ptr.end_vertex.name==destination:
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print("Edge already present")
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else:
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temp = EdgeNode(v)
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edge_ptr.next_edge = temp
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self._nedges += 1
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def delete_vertex(self, vertex_name):
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self._delete_from_edge_lists(vertex_name)
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self._delete_from_vertex_list(vertex_name)
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# Delete incoming edges
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def _delete_from_edge_lists(self, vertex_name):
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vertex_ptr = None
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edge_ptr = None
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vertex_ptr = self._start
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while vertex_ptr != None:
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if vertex_ptr.first_edge != None:
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if vertex_ptr.first_edge.end_vertex.name == vertex_name:
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vertex_ptr.first_edge = vertex_ptr.first_edge.next_edge
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self._nedges -= 1
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continue
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edge_ptr = vertex_ptr.first_edge
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while edge_ptr.next_edge != None:
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if edge_ptr.next_edge.end_vertex.name == vertex_name:
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edge_ptr.next_edge = edge_ptr.next_edge.next_edge
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self._nedges -= 1
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continue
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edge_ptr = edge_ptr.next_edge
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vertex_ptr = vertex_ptr.next_vertex
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# Delete outgoing edges and vertex
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def _delete_from_vertex_list(self, vertex_name):
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vertex_ptr = None
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temp_vertex = None
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edge_ptr = None
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if self._start == None:
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print("No vertices to be deleted")
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return
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if self._start.name == vertex_name:
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temp_vertex = self._start
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self._start = self._start.next_vertex
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else: # vertex to be deleted is in between or at last
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vertex_ptr = self._start
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while vertex_ptr.next_vertex != None:
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if vertex_ptr.next_vertex.name == vertex_name:
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break
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vertex_ptr = vertex_ptr.next_vertex
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if vertex_ptr.next_vertex != None:
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temp_vertex = vertex_ptr.next_vertex
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vertex_ptr.next_vertex = vertex_ptr.next_vertex.next_vertex
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else:
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print("Vertex not found")
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if temp_vertex != None:
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edge_ptr = temp_vertex.first_edge
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while edge_ptr != None:
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edge_ptr = edge_ptr.next_edge
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self._nedges -= 1
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self._nvertices -= 1
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def delete_edge(self, source, destination):
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vertex_ptr = None
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edge_ptr = None
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vertex_ptr = self._find_vertex(source)
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if vertex_ptr == None:
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print("Edge not found")
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else:
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edge_ptr = vertex_ptr.first_edge
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if edge_ptr == None:
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print("Edge not found")
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else:
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if edge_ptr.end_vertex.name == destination:
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vertex_ptr.first_edge = edge_ptr.next_edge
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self._nedges -= 1
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else:
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while edge_ptr.next_edge != None:
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if edge_ptr.next_edge.end_vertex.name == destination:
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break
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edge_ptr = edge_ptr.next_edge
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if edge_ptr.next_edge == None:
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print("Edge not found")
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else:
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edge_ptr.next_edge = edge_ptr.next_edge.next_edge
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self._nedges -= 1
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def display(self):
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vertex_ptr = None
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edge_ptr = None
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vertex_ptr = self._start
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while vertex_ptr != None:
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print("Vertex : " + vertex_ptr.name)
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edge_ptr = vertex_ptr.first_edge
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while edge_ptr != None:
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print("Edge : " + vertex_ptr.name + " -> " + edge_ptr.end_vertex.name)
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edge_ptr = edge_ptr.next_edge
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vertex_ptr = vertex_ptr.next_vertex
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def edge_exists(self, source, destination):
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vertex_ptr = None
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edge_ptr = None
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edge_found = False
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vertex_ptr = self._find_vertex(source)
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if vertex_ptr != None:
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edge_ptr = vertex_ptr.first_edge
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while edge_ptr != None:
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if edge_ptr.end_vertex.name == destination:
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edge_found = True
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break
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edge_ptr = edge_ptr.next_edge
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return edge_found
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def get_outdegree(self, vertex):
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vertex_ptr = None
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edge_ptr = None
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outdegree = 0
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vertex_ptr = self._find_vertex(vertex)
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if vertex_ptr == None:
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raise Exception("Invalid Vertex")
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edge_ptr = vertex_ptr.first_edge
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while edge_ptr != None:
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outdegree += 1
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edge_ptr = edge_ptr.next_edge
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return outdegree
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def get_indegree(self, vertex):
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vertex_ptr = None
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edge_ptr = None
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indegree = 0
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if self._find_vertex(vertex) == None:
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raise Exception("Invalid Vertex")
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vertex_ptr = self._start
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while vertex_ptr != None:
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edge_ptr = vertex_ptr.first_edge
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while edge_ptr != None:
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if edge_ptr.end_vertex.name == vertex:
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indegree += 1
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edge_ptr = edge_ptr.next_edge
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vertex_ptr = vertex_ptr.next_vertex
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return indegree
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if __name__ == '__main__':
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d_graph = DirectedGraphList()
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try:
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# Creating the graph, inserting the vertices and edges
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d_graph.insert_vertex("0")
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d_graph.insert_vertex("1")
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d_graph.insert_vertex("2")
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d_graph.insert_vertex("3")
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d_graph.insert_edge("0","3")
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d_graph.insert_edge("1","2")
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d_graph.insert_edge("2","3")
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d_graph.insert_edge("3","1")
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d_graph.insert_edge("0","2")
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# Display the graph
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d_graph.display()
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print()
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# Deleting an edge
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d_graph.delete_edge("0","2")
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# Display the graph
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d_graph.display()
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print()
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# Deleting a vertex
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d_graph.delete_vertex("0")
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# Display the graph
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d_graph.display()
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print()
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# Check if there is an edge between two vertices
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print("Edge exist : ", d_graph.edge_exists("2","3"))
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# Display Outdegree and Indegree of a vertex
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print("Outdegree : ", d_graph.get_outdegree("3"))
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print("Indegree : ", d_graph.get_indegree("3"))
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except Exception as e:
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print(e)
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‎graphs/adjacency-matrix/README.md

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# Data Structures and Algorithms (DSA) In Python
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This repository is for the students of book [Data Structures and Algorithms In Python](http://coursegalaxy.com/) and online courses available on CourseGalaxy. It contains the source code of all the programs used in the book and courses.
4+
5+
### About the DSA Masterclass Courses
6+
* Thoroughly detailed courses with complete working programs
7+
* Contains lots of animations to help you visualize the concepts
8+
* Includes various Data Structures and Algorithms
9+
* Builds a solid foundation in Data Structures and Algorithms
10+
* Prepares you for coding interviews
11+
* Lifetime Access
12+
13+
### DSA Masterclass Courses on [CourseGalaxy](http://coursegalaxy.com/)
14+
15+
[![data-structures-algorithms-python](https://user-images.githubusercontent.com/96913690/200234827-86aec10a-bfab-4371-91fc-e2be855ff1ff.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-python?coupon_code=GITHUB75PER)
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[![data-structures-algorithms-java](https://user-images.githubusercontent.com/96913690/200234744-14a5ed97-085f-44f3-9298-979c2053c580.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-java?coupon_code=GITHUB75PER)
17+
[![data-structures-algorithms-c](https://user-images.githubusercontent.com/96913690/200234592-25d33957-0e9e-4cc0-b324-2a73325aca85.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-c?coupon_code=GITHUB75PER)
18+
[![data-structures-algorithms-csharp](https://user-images.githubusercontent.com/96913690/200234905-67b85dfd-20c4-4f4b-afd2-e10d3568fff8.jpg)](https://coursegalaxy.usefedora.com/p/data-structures-algorithms-csharp?coupon_code=GITHUB75PER)
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## Copyright
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© Copyright Suresh Kumar Srivastava : All rights reserved.
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Not to be used for commercial purposes.

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