# Reverse delete algorithm for minimum spanning tree

Here given code implementation process.

``````import java.util.ArrayList;
/*
Java Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
// edge weight or cost
public int weight;
public int u;
public int v;
public Edge next;
public Edge(int weight, int u, int v)
{
this.weight = weight;
this.u = u;
this.v = v;
this.next = null;
}
}
public class Graph
{
public int vertices;
public ArrayList < ArrayList < Integer >> adgeList;
public Edge edges;
public int edgeCount;
public Graph(int vertices)
{
this.vertices = vertices;
this.adgeList = new ArrayList < ArrayList < Integer >> (vertices);
this.edges = null;
this.edgeCount = 0;
for (int i = 0; i < this.vertices; ++i)
{
}
}
public void addEdge(int u, int v, int w)
{
if (u < 0 || u >= this.vertices || v < 0 || v >= this.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
Edge e = new Edge(w, u, v);
// Add edge in decreasing order
if (this.edges == null)
{
// First edge
this.edges = e;
}
else if (this.edges.weight <= e.weight)
{
e.next = this.edges;
this.edges = e;
}
else
{
Edge temp = this.edges;
// Find position to add new edge
while (temp.next != null && temp.next.weight > e.weight)
{
temp = temp.next;
}
e.next = temp.next;
temp.next = e;
}
this.edgeCount = this.edgeCount + 1;
}
// Perform DFS
public void findDFS(int v, boolean[] visited)
{
// Indicates the current vertex is visited
visited[v] = true;
// iterate edges of v node
for (int i = 0; i < this.adgeList.get(v).size(); i++)
{
{
}
}
}
// Check that graph start vertices are reach to all other vertices or not
public boolean isConnected()
{
boolean[] visited = new boolean[this.vertices];
// Set the initial visited vertices
for (int i = 0; i < this.vertices; ++i)
{
visited[i] = false;
}
this.findDFS(0, visited);
for (int i = 1; i < this.vertices; i++)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
}
return true;
}
public void printGraph()
{
for (int i = 0; i < this.vertices; ++i)
{
System.out.print(" \n [" + i + "] :");
// iterate edges of i node
for (int j = 0; j < this.adgeList.get(i).size(); j++)
{
}
}
}
public void reverseDeleteMST()
{
int result = 0;
// Get first higher edge
Edge point = this.edges;
System.out.println("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point != null)
{
// Remove the current weight edge of node from u to v and v to u
if (isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point.weight;
// Display edge
System.out.print(" (" + point.u + ", " + point.v + ") \n");
}
// Visit next smaller weight edge
point = point.next;
}
System.out.println("Calculated total weight of MST is " + result);
}
public static void main(String[] args)
{
Graph g = new Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}
}``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````// Include header file
#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;
/*
C++ Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
public:
// edge weight or cost
int weight;
int u;
int v;
Edge *next;
Edge(int weight, int u, int v)
{
this->weight = weight;
this->u = u;
this->v = v;
this->next = NULL;
}
};
class Graph
{
public: int vertices;
Edge *edges;
int edgeCount;
Graph(int vertices)
{
this->vertices = vertices;
this->edges = NULL;
this->edgeCount = 0;
for(int i = 0 ; i < vertices; ++i)
{
}
}
void addEdge(int u, int v, int w)
{
if (u < 0 || u >= this->vertices || v < 0 || v >= this->vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
Edge *e = new Edge(w, u, v);
// Add edge in decreasing order
if (this->edges == NULL)
{
// First edge
this->edges = e;
}
else if (this->edges->weight <= e->weight)
{
e->next = this->edges;
this->edges = e;
}
else
{
Edge *temp = this->edges;
// Find position to add new edge
while (temp->next != NULL && temp->next->weight > e->weight)
{
temp = temp->next;
}
e->next = temp->next;
temp->next = e;
}
this->edgeCount = this->edgeCount + 1;
}
// Perform DFS
void findDFS(int v, bool visited[])
{
// Indicates the current vertex is visited
visited[v] = true;
// iterate edges of v node
for (int i = 0; i < this->adgeList.at(v).size(); i++)
{
{
}
}
}
// Check that graph start vertices are reach to all other vertices or not
bool isConnected()
{
bool visited[this->vertices];
// Set the initial visited vertices
for (int i = 0; i < this->vertices; ++i)
{
visited[i] = false;
}
this->findDFS(0, visited);
for (int i = 1; i < this->vertices; i++)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
}
return true;
}
void printGraph()
{
cout << "\n Graph Adjacency List ";
for (int i = 0; i < this->vertices; ++i)
{
cout << " \n [" << i << "] :";
// iterate edges of i node
for (int j = 0; j < this->adgeList.at(i).size(); j++)
{
cout << "  " << this->adgeList.at(i).at(j);
}
}
}
void reverseDeleteMST()
{
int result = 0;
// Get first higher edge
Edge *point = this->edges;
cout << "\n\nConnected node by Edges in MST" << endl;
// iterates the edge from high to low order
while (point != NULL)
{

// Remove the current weight edge of node from u to v and v to u

if (this->isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point->weight;
// Display edge
cout << " (" << point->u << ", " << point->v << ") \n";
}
// Visit next smaller weight edge
point = point->next;
}
cout << "Calculated total weight of MST is " << result << endl;
}
};
int main()
{
Graph *g = new Graph(8);
// Display graph element
g->printGraph();
// Find MST
g->reverseDeleteMST();
return 0;
}``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````// Include namespace system
using System;
using System.Collections.Generic;
/*
Csharp Program
Reverse delete algorithm for minimum spanning tree
*/
public class Edge
{
// edge weight or cost
public int weight;
public int u;
public int v;
public Edge next;
public Edge(int weight, int u, int v)
{
this.weight = weight;
this.u = u;
this.v = v;
this.next = null;
}
}
public class Graph
{
public int vertices;
public List < List < int >> adgeList;
public Edge edges;
public int edgeCount;
public Graph(int vertices)
{
this.vertices = vertices;
this.adgeList = new List < List < int >> (vertices);
this.edges = null;
this.edgeCount = 0;
for (int i = 0; i < this.vertices; ++i)
{
}
}
public void addEdge(int u, int v, int w)
{
if (u < 0 || u >= this.vertices || v < 0 || v >= this.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
Edge e = new Edge(w, u, v);
// Add edge in decreasing order
if (this.edges == null)
{
// First edge
this.edges = e;
}
else if (this.edges.weight <= e.weight)
{
e.next = this.edges;
this.edges = e;
}
else
{
Edge temp = this.edges;
// Find position to add new edge
while (temp.next != null && temp.next.weight > e.weight)
{
temp = temp.next;
}
e.next = temp.next;
temp.next = e;
}
this.edgeCount = this.edgeCount + 1;
}
// Perform DFS
public void findDFS(int v, Boolean[] visited)
{
// Indicates the current vertex is visited
visited[v] = true;
// iterate edges of v node
for (int i = 0; i < this.adgeList[v].Count; i++)
{
{
}
}
}
// Check that graph start vertices are reach to all other vertices or not
public Boolean isConnected()
{
Boolean[] visited = new Boolean[this.vertices];
// Set the initial visited vertices
for (int i = 0; i < this.vertices; ++i)
{
visited[i] = false;
}
this.findDFS(0, visited);
for (int i = 1; i < this.vertices; i++)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
}
return true;
}
public void printGraph()
{
for (int i = 0; i < this.vertices; ++i)
{
Console.Write(" \n [" + i + "] :");
// iterate edges of i node
for (int j = 0; j < this.adgeList[i].Count; j++)
{
}
}
}
public void reverseDeleteMST()
{
int result = 0;
// Get first higher edge
Edge point = this.edges;
Console.WriteLine("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point != null)
{
// Remove the current weight edge of node from u to v and v to u
if (this.isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point.weight;
// Display edge
Console.Write(" (" + point.u + ", " + point.v + ") \n");
}
// Visit next smaller weight edge
point = point.next;
}
Console.WriteLine("Calculated total weight of MST is " + result);
}
public static void Main(String[] args)
{
Graph g = new Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}
}``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````<?php
/*
Php Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
// edge weight or cost
public \$weight;
public \$u;
public \$v;
public \$next;
public  function __construct(\$weight, \$u, \$v)
{
\$this->weight = \$weight;
\$this->u = \$u;
\$this->v = \$v;
\$this->next = NULL;
}
}
class Graph
{
public \$vertices;
public \$edges;
public \$edgeCount;
public  function __construct(\$vertices)
{
\$this->vertices = \$vertices;
\$this->edges = NULL;
\$this->edgeCount = 0;
for (\$i = 0; \$i < \$this->vertices; ++\$i)
{
}
}
{
if (\$u < 0 || \$u >= \$this->vertices || \$v < 0 || \$v >= \$this->vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
\$e = new Edge(\$w, \$u, \$v);
// Add edge in decreasing order
if (\$this->edges == NULL)
{
// First edge
\$this->edges = \$e;
}
else if (\$this->edges->weight <= \$e->weight)
{
\$e->next = \$this->edges;
\$this->edges = \$e;
}
else
{
\$temp = \$this->edges;
// Find position to add new edge
while (\$temp->next != NULL && \$temp->next->weight > \$e->weight)
{
\$temp = \$temp->next;
}
\$e->next = \$temp->next;
\$temp->next = \$e;
}
\$this->edgeCount = \$this->edgeCount + 1;
}
// Perform DFS
public  function findDFS(\$v, &\$visited)
{
// Indicates the current vertex is visited
\$visited[\$v] = true;

// iterate edges of v node
{
if (\$visited[\$value] == false)
{
\$this->findDFS(\$value, \$visited);
}
}
}
// Check that graph start vertices are reach to all other vertices or not
public  function isConnected()
{
\$visited = array_fill(0, \$this->vertices, false);
\$this->findDFS(0, \$visited);
for (\$i = 1; \$i < \$this->vertices; \$i++)
{
if (\$visited[\$i] == false)
{
// When [i] vertices are not visit
return false;
}
}
return true;
}
public  function printGraph()
{
for (\$i = 0; \$i < \$this->vertices; ++\$i)
{
echo(" \n [".\$i."] :");
// iterate edges of i node
for (\$j = 0; \$j < count(\$this->adgeList[\$i]); \$j++)
{
}
}
}
public  function reverseDeleteMST()
{
\$result = 0;
// Get first higher edge
\$point = \$this->edges;
echo("\n\nConnected node by Edges in MST"."\n");
// iterates the edge from high to low order
while (\$point != NULL)
{

// Remove the current weight edge of node from u to v and v to u
if ((\$key = array_search(\$point->v,

}

if ((\$key = array_search(\$point->u,

}

if (\$this->isConnected() == false )
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
\$result += \$point->weight;
// Display edge
echo(" (".\$point->u.
", ".\$point->v.
") \n");
}
// Visit next smaller weight edge
\$point = \$point->next;
}
echo("Calculated total weight of MST is ".\$result.
"\n");
}
}

function main()
{
\$g = new Graph(8);
// Display graph element
\$g->printGraph();
// Find MST
\$g->reverseDeleteMST();
}
main();``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````/*
Node JS Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
constructor(weight, u, v)
{
this.weight = weight;
this.u = u;
this.v = v;
this.next = null;
}
}
class Graph
{
constructor(vertices)
{
this.vertices = vertices;
this.edges = null;
this.edgeCount = 0;
for (var i = 0; i < this.vertices; ++i)
{
}
}
{
if (u < 0 || u >= this.vertices || v < 0 || v >= this.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
var e = new Edge(w, u, v);
// Add edge in decreasing order
if (this.edges == null)
{
// First edge
this.edges = e;
}
else if (this.edges.weight <= e.weight)
{
e.next = this.edges;
this.edges = e;
}
else
{
var temp = this.edges;
// Find position to add new edge
while (temp.next != null && temp.next.weight > e.weight)
{
temp = temp.next;
}
e.next = temp.next;
temp.next = e;
}
this.edgeCount = this.edgeCount + 1;
}
// Perform DFS
findDFS(v, visited)
{
// Indicates the current vertex is visited
visited[v] = true;
// iterate edges of v node
for (var i = 0; i < this.adgeList[v].length; i++)
{
{
}
}
}
// Check that graph start vertices are reach to all other vertices or not
isConnected()
{
var visited = Array(this.vertices).fill(false);
this.findDFS(0, visited);
for (var i = 1; i < this.vertices; i++)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
}
return true;
}
printGraph()
{
for (var i = 0; i < this.vertices; ++i)
{
process.stdout.write(" \n [" + i + "] :");
// iterate edges of i node
for (var j = 0; j < this.adgeList[i].length; j++)
{
}
}
}
reverseDeleteMST()
{
var result = 0;
// Get first higher edge
var point = this.edges;
var index = 0;
console.log("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point != null)
{
// Remove the current weight edge of node from u to v and v to u
if (index !== -1)
{
}
if (index !== -1)
{
}
if (this.isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point.weight;
// Display edge
process.stdout.write(" (" + point.u + ", " + point.v + ") \n");
}
// Visit next smaller weight edge
point = point.next;
}
console.log("Calculated total weight of MST is " + result);
}
}

function main()
{
var g = new Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}
main();``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````#    Python 3 Program
#    Reverse delete algorithm for minimum spanning tree
class Edge :
#  edge weight or cost
def __init__(self, weight, u, v) :
self.weight = weight
self.u = u
self.v = v
self.next = None

class Graph :
def __init__(self, vertices) :
self.vertices = vertices
self.edges = None
self.edgeCount = 0
i = 0
while (i < self.vertices) :
i += 1

def addEdge(self, u, v, w) :
if (u < 0 or u >= self.vertices or v < 0 or v >= self.vertices) :
return

#  Collect descending order sorted edges
#  Create new edge
e = Edge(w, u, v)
#  Add edge in decreasing order
if (self.edges == None) :
#  First edge
self.edges = e
elif (self.edges.weight <= e.weight) :
e.next = self.edges
self.edges = e
else :
temp = self.edges
#  Find position to add new edge
while (temp.next != None and temp.next.weight > e.weight) :
temp = temp.next

e.next = temp.next
temp.next = e

self.edgeCount = self.edgeCount + 1

#  Perform DFS
def findDFS(self, v, visited) :
#  Indicates the current vertex is visited
visited[v] = True
i = 0
#  iterate edges of v node

i += 1

#  Check that graph start vertices are reach to all other vertices or not
def isConnected(self) :
visited = [False] * (self.vertices)
i = 0
#  Set the initial visited vertices
while (i < self.vertices) :
visited[i] = False
i += 1

self.findDFS(0, visited)
i = 1
while (i < self.vertices) :
if (visited[i] == False) :
#  When [i] vertices are not visit
return False

i += 1

return True

def printGraph(self) :
print("\n Graph Adjacency List ", end = "")
i = 0
while (i < self.vertices) :
print(" \n [", i ,"] :", end = "")
j = 0
#  iterate edges of i node
print("  ", self.adgeList[i][j], end = "")
j += 1

i += 1

def reverseDeleteMST(self) :
result = 0
#  Get first higher edge
point = self.edges
print("\n\nConnected node by Edges in MST")
#  iterates the edge from high to low order
while (point != None) :
#  Remove the current weight edge of node from u to v and v to u
if (self.isConnected() == False) :
#  When delete edge are create problems ().
#  Then they are add back into graph
#  Update weight
result += point.weight
#  Display edge
print(" (", point.u ,", ", point.v ,") ")

#  Visit next smaller weight edge
point = point.next

print("Calculated total weight of MST is ", result)

def main() :
g = Graph(8)
#  Display graph element
g.printGraph()
#  Find MST
g.reverseDeleteMST()

if __name__ == "__main__": main()``````

#### input

`````` Graph Adjacency List
[ 0 ] :   1   3
[ 1 ] :   0   2   6   7
[ 2 ] :   1   5   7
[ 3 ] :   0   4   7
[ 4 ] :   3   5   6   7
[ 5 ] :   2   4   6
[ 6 ] :   1   4   5
[ 7 ] :   1   2   3   4

Connected node by Edges in MST
( 2 ,  5 )
( 4 ,  5 )
( 1 ,  6 )
( 0 ,  1 )
( 2 ,  7 )
( 1 ,  2 )
( 0 ,  3 )
Calculated total weight of MST is  39``````
``````#    Ruby Program
#    Reverse delete algorithm for minimum spanning tree
class Edge
# Define the accessor and reader of class Edge
attr_accessor :weight, :u, :v, :next
#  edge weight or cost
def initialize(weight, u, v)
self.weight = weight
self.u = u
self.v = v
self.next = nil
end

end

class Graph
# Define the accessor and reader of class Graph
def initialize(vertices)
self.vertices = vertices
self.edges = nil
self.edgeCount = 0
i = 0
while (i < self.vertices)
i += 1
end

end

if (u < 0 || u >= self.vertices || v < 0 || v >= self.vertices)
return
end

#  Collect descending order sorted edges
#  Create new edge
e = Edge.new(w, u, v)
#  Add edge in decreasing order
if (self.edges == nil)
#  First edge
self.edges = e
elsif (self.edges.weight <= e.weight)
e.next = self.edges
self.edges = e
else

temp = self.edges
#  Find position to add new edge
while (temp.next != nil && temp.next.weight > e.weight)
temp = temp.next
end

e.next = temp.next
temp.next = e
end

self.edgeCount = self.edgeCount + 1
end

#  Perform DFS
def findDFS(v, visited)
#  Indicates the current vertex is visited
visited[v] = true
#  iterate edges of v node
if (visited[i] == false)
self.findDFS(i, visited)
end
i += 1
end

end

#  Check that graph start vertices are reach to all other vertices or not
def isConnected()
visited = Array.new(self.vertices) {false}
i = 0
#  Set the initial visited vertices
while (i < self.vertices)
visited[i] = false
i += 1
end

self.findDFS(0, visited)
i = 1
while (i < self.vertices)
if (visited[i] == false)
#  When [i] vertices are not visit
return false
end

i += 1
end

return true
end

def printGraph()
i = 0
while (i < self.vertices)
print(" \n [", i ,"] :")
j = 0
#  iterate edges of i node
j += 1
end

i += 1
end

end

def reverseDeleteMST()
result = 0
#  Get first higher edge
point = self.edges
print("\n\nConnected node by Edges in MST", "\n")
#  iterates the edge from high to low order
while (point != nil)

#  Remove the current weight edge of node from u to v and v to u

if (self.isConnected() == false)
#  When delete edge are create problems ().
#  Then they are add back into graph
#  Update weight
result += point.weight
#  Display edge
print(" (", point.u ,", ", point.v ,") \n")
end

#  Visit next smaller weight edge
point = point.next
end

print("Calculated total weight of MST is ", result, "\n")
end

end

def main()
g = Graph.new(8)
#  Display graph element
g.printGraph()
#  Find MST
g.reverseDeleteMST()
end

main()``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39
``````
``````import scala.collection.mutable._;
/*
Scala Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge(
// edge weight or cost
var weight: Int,
var u: Int,
var v: Int,
var next: Edge)
{
def this(weight: Int, u: Int, v: Int)
{
this(weight, u,v,null);
}
}
class Graph(var vertices: Int,
var edges: Edge,
var edgeCount: Int)
{
def this(vertices: Int)
{
this(vertices,new ArrayBuffer[ArrayBuffer[Int]](vertices), null,0);
var i: Int = 0;
while (i < this.vertices)
{
i += 1;
}
}
def addEdge(u: Int, v: Int, w: Int): Unit = {
if (u < 0 || u >= this.vertices || v < 0 || v >= this.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
var e: Edge = new Edge(w, u, v);
// Add edge in decreasing order
if (this.edges == null)
{
// First edge
this.edges = e;
}
else if (this.edges.weight <= e.weight)
{
e.next = this.edges;
this.edges = e;
}
else
{
var temp: Edge = this.edges;
// Find position to add new edge
while (temp.next != null && temp.next.weight > e.weight)
{
temp = temp.next;
}
e.next = temp.next;
temp.next = e;
}
this.edgeCount = this.edgeCount + 1;
}
// Perform DFS
def findDFS(v: Int, visited: Array[Boolean]): Unit = {
// Indicates the current vertex is visited
visited(v) = true;
var i: Int = 0;
// iterate edges of v node
{
{
}
i += 1;
}
}
// Check that graph start vertices are reach to all other vertices or not
def isConnected(): Boolean = {
var visited: Array[Boolean] = Array.fill[Boolean](this.vertices)(false);
this.findDFS(0, visited);
var i: Int = 1;
while (i < this.vertices)
{
if (visited(i) == false)
{
// When [i] vertices are not visit
return false;
}
i += 1;
}
return true;
}
def printGraph(): Unit = {
var i: Int = 0;
while (i < this.vertices)
{
print(" \n [" + i + "] :");
var j: Int = 0;
// iterate edges of i node
{
j += 1;
}
i += 1;
}
}
def reverseDeleteMST(): Unit = {
var result: Int = 0;
// Get first higher edge
var point: Edge = this.edges;
println("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point != null)
{
// Remove the current weight edge of node from u to v and v to u
if (isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point.weight;
// Display edge
print(" (" + point.u + ", " + point.v + ") \n");
}
// Visit next smaller weight edge
point = point.next;
}
println("Calculated total weight of MST is " + result);
}
}
object Main
{
def main(args: Array[String]): Unit = {
var g: Graph = new Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}
}``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````
``````import Foundation;
/*
Swift 4 Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
// edge weight or cost
var weight: Int;
var u: Int;
var v: Int;
var next: Edge? ;
init(_ weight: Int, _ u: Int, _ v: Int)
{
self.weight = weight;
self.u = u;
self.v = v;
self.next = nil;
}
}
class Graph
{
var vertices: Int;
[Int]
];
var edges: Edge? ;
var edgeCount: Int;
init(_ vertices: Int)
{
self.vertices = vertices;
self.edges = nil;
self.edgeCount = 0;
var i = 0;
while (i < self.vertices)
{
i += 1;
}
}
func addEdge(_ u: Int, _ v: Int, _ w: Int)
{
if (u < 0 || u >= self.vertices || v < 0 || v >= self.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
let e = Edge(w, u, v);
// Add edge in decreasing order
if (self.edges == nil)
{
// First edge
self.edges = e;
}
else if (self.edges!.weight <= e.weight)
{
e.next = self.edges;
self.edges = e;
}
else
{
var temp = self.edges;
// Find position to add new edge
while (temp!.next  != nil && temp!.next!.weight > e.weight)
{
temp = temp!.next;
}
e.next = temp!.next;
temp!.next = e;
}
self.edgeCount = self.edgeCount + 1;
}
// Perform DFS
func findDFS(_ v: Int, _ visited: inout[Bool])
{
// Indicates the current vertex is visited
visited[v] = true;
var i = 0;
// iterate edges of v node
{
{
}
i += 1;
}
}
// Check that graph start vertices are reach to all other vertices or not
func isConnected() -> Bool
{
var visited = Array(repeating: false, count: self.vertices);

self.findDFS(0, &visited);
var i = 1;
while (i < self.vertices)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
i += 1;
}
return true;
}
func printGraph()
{
print("\n Graph Adjacency List ", terminator: "");
var i = 0;
while (i < self.vertices)
{
print(" \n [", i ,"] :", terminator: "");
var j = 0;
// iterate edges of i node
{
j += 1;
}
i += 1;
}
}
func reverseDeleteMST()
{
var result = 0;
// Get first higher edge
var point = self.edges;
print("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point  != nil)
{
// Remove the current weight edge of node from u to v and v to u
if let k1 = self.adgeList[point!.u].index(of:point!.v) {
}
if let k2 = self.adgeList[point!.v].index(of:point!.u) {
}

if (self.isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point!.weight;
// Display edge
print(" (", point!.u ,", ", point!.v ,") ");
}
// Visit next smaller weight edge
point = point!.next;
}
print("Calculated total weight of MST is ", result);
}
}
func main()
{
let g = Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}
main();``````

#### input

`````` Graph Adjacency List
[ 0 ] :   1   3
[ 1 ] :   0   2   6   7
[ 2 ] :   1   5   7
[ 3 ] :   0   4   7
[ 4 ] :   3   5   6   7
[ 5 ] :   2   4   6
[ 6 ] :   1   4   5
[ 7 ] :   1   2   3   4

Connected node by Edges in MST
( 2 ,  5 )
( 4 ,  5 )
( 1 ,  6 )
( 0 ,  1 )
( 2 ,  7 )
( 1 ,  2 )
( 0 ,  3 )
Calculated total weight of MST is  39``````
``````/*
Kotlin Program
Reverse delete algorithm for minimum spanning tree
*/
class Edge
{
// edge weight or cost
var weight: Int;
var u: Int;
var v: Int;
var next: Edge ? ;
constructor(weight: Int, u: Int, v: Int)
{
this.weight = weight;
this.u = u;
this.v = v;
this.next = null;
}
}
class Graph
{
var vertices: Int;
var edges: Edge ? ;
var edgeCount: Int;
constructor(vertices: Int)
{
this.vertices = vertices;
this.edges = null;
this.edgeCount = 0;
var i: Int = 0;
while (i < this.vertices)
{
i += 1;
}
}
fun addEdge(u: Int, v: Int, w: Int): Unit
{
if (u < 0 || u >= this.vertices || v < 0 || v >= this.vertices)
{
return;
}
// Collect descending order sorted edges
// Create new edge
val e: Edge = Edge(w, u, v);
// Add edge in decreasing order
if (this.edges == null)
{
// First edge
this.edges = e;
}
else if (this.edges!!.weight <= e.weight)
{
e.next = this.edges;
this.edges = e;
}
else
{
var temp: Edge? = this.edges;
// Find position to add new edge
while ( temp?.next != null
&& temp.next!!.weight > e.weight)
{
temp = temp.next;
}
e.next = temp?.next;
temp?.next = e;
}
this.edgeCount = this.edgeCount + 1;
}
// Perform DFS
fun findDFS(v: Int, visited: Array < Boolean > ): Unit
{
// Indicates the current vertex is visited
visited[v] = true;
var i: Int = 0;
// iterate edges of v node
{
{
}
i += 1;
}
}
// Check that graph start vertices are reach to all other vertices or not
fun isConnected(): Boolean
{
val visited: Array < Boolean > = Array(this.vertices)
{
false
};
this.findDFS(0, visited);
var i: Int = 1;
while (i < this.vertices)
{
if (visited[i] == false)
{
// When [i] vertices are not visit
return false;
}
i += 1;
}
return true;
}
fun printGraph(): Unit
{
var i: Int = 0;
while (i < this.vertices)
{
print(" \n [" + i + "] :");
var j: Int = 0;
// iterate edges of i node
{
j += 1;
}
i += 1;
}
}
fun reverseDeleteMST(): Unit
{
var result: Int = 0;
// Get first higher edge
var point: Edge ? = this.edges;
println("\n\nConnected node by Edges in MST");
// iterates the edge from high to low order
while (point != null)
{
// Remove the current weight edge of node from u to v and v to u
if (this.isConnected() == false)
{
// When delete edge are create problems ().
// Then they are add back into graph
// Update weight
result += point.weight;
// Display edge
print(" (" + point.u + ", " + point.v + ") \n");
}
// Visit next smaller weight edge
point = point.next;
}
println("Calculated total weight of MST is " + result);
}
}
fun main(args: Array < String > ): Unit
{
val g: Graph = Graph(8);
// Display graph element
g.printGraph();
// Find MST
g.reverseDeleteMST();
}``````

#### input

`````` Graph Adjacency List
[0] :  1  3
[1] :  0  2  6  7
[2] :  1  5  7
[3] :  0  4  7
[4] :  3  5  6  7
[5] :  2  4  6
[6] :  1  4  5
[7] :  1  2  3  4

Connected node by Edges in MST
(2, 5)
(4, 5)
(1, 6)
(0, 1)
(2, 7)
(1, 2)
(0, 3)
Calculated total weight of MST is 39``````

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