Added Prim's algoritm.c

Author: UG-SEP

Graph/Prim's algorithm.c

@@ -0,0 +1,219 @@
+/*                                                               Prim's Algorithm                                               
+             This is Prim's algorithm to find the lowest cost to traverse it all vertex of a graph or MST(Minimal Spanning Tree)                                              */
+#include<stdio.h>
+#include<stdlib.h>
+// node type structure
+struct node
+{
+    int no;
+    int PI;
+    int Key;
+    struct node *next;
+};
+// graph type structure
+struct Graph
+{
+    int V;
+    int E;
+};
+// this function initialize value in Graph structure members
+struct Graph* create_graph(int V,int E)
+{
+    // Graph structure pointer to store value
+ struct Graph *G;
+ G=(struct Graph*)malloc(sizeof(struct Graph));
+ G->E=E;
+ G->V=V;
+ return(G);
+}
+// function to check the least priority Key or distance node no. and return it
+int less_priority(struct node *Start)
+{
+    int less=0,no=0;
+    less=Start->Key;
+    no=Start->no;
+    Start=Start->next;
+    // until start is not equal to 0 the loop will run
+    while(Start!=NULL)
+    {
+        if(Start->Key<less)
+        {
+            less=Start->Key;
+            no=Start->no;
+        }
+        Start=Start->next;
+    }
+    return(no);
+}
+// this function insert the a node
+void insertion(struct node **Start,int no)
+{
+    struct node *temp,*t;
+    temp=(struct node*)malloc(sizeof(struct node));
+    temp->no=no;
+    temp->PI=0;
+    temp->Key=1000;
+    temp->next=NULL;
+    if(*Start==NULL)
+    { temp->Key=0;
+        *Start=temp;
+       }
+    else
+    {
+        t=*Start;
+        while(t->next!=NULL)
+            t=t->next;
+        t->next=temp;
+    }
+}
+// remove node from the queue
+struct node* deletion(struct node **Start)
+{ int check=0;
+struct node *temp,*t,*pre;
+    temp=(struct node*)malloc(sizeof(struct node));
+    // finding the less priority node no.
+    check=less_priority(*Start);
+    // is start no. member is equal to check variable
+    if((*Start)->no==check)
+    {
+        temp->no=(*Start)->no;
+        temp->Key=(*Start)->Key;
+        temp->PI=(*Start)->PI;
+        temp->next=NULL;
+        t=*Start;
+        *Start=(*Start)->next;
+        free(t);
+    }
+    else
+    { t=*Start;
+        while(t->next!=NULL)
+        {
+            pre=t;
+            t=t->next;
+            if(check==t->no)
+                break;
+            }
+            temp->no=t->no;
+            temp->PI=t->PI;
+            temp->Key=t->Key;
+            temp->next=NULL;
+            pre->next=t->next;
+            free(t);
+    }
+    return(temp);
+}
+// this function check whether the particular node is in the queue or not
+int check_in_q(int n,struct node *Start)
+{
+   while(Start!=NULL)
+   {
+       if(Start->no==n)
+        return(1);
+       Start=Start->next;
+   }
+   return(0);
+}
+int get_n(int n,struct node *Start)
+{ int Key;
+// finding the distance of the node no. match with the n(node number) and returning the distance
+    while(Start!=NULL)
+    {
+        if(n==Start->no)
+        {
+            Key=Start->Key;
+            break;
+        }
+        Start=Start->next;
+    }
+    return(Key);
+}
+//this function change the Key(distance) and PI(Parent node) value with the given arguments
+void change(int n,struct node **Start,int Key,int PI)
+{
+    struct node *temp;
+    if((*Start)->no==n)
+    {
+        (*Start)->Key=Key;
+        (*Start)->PI=PI;
+    }
+    else
+    {
+      temp=*Start;
+      while(temp!=NULL)
+      {
+          if(temp->no==n)
+          {
+              temp->Key=Key;
+              temp->PI=PI;
+              break;
+          }
+          temp=temp->next;
+      }
+    }
+}
+//the main logic to find lowest cost traverse
+void Prims(struct node **Start,struct Graph *G)
+{ int e1,i,n,w;
+    struct node *temp;
+    int t,cost=0;
+    // run until start is not equal to 0
+    while(*Start!=NULL)
+    {
+        //take the less priority node
+    temp=deletion(Start);
+    // increase cost
+    cost+=temp->Key;
+    printf("Enter the no. of nodes connected to V%d",temp->no);
+    scanf("%d",&e1);
+    for(i=0;i<e1;i++)
+    {
+        printf("enter the node no of v%d and weight",temp->no);
+        scanf("%d%d",&n,&w);
+        if(1==check_in_q(n,*Start))
+        {
+            t=get_n(n,*Start);
+            if(w<t)
+                change(n,Start,w,e1);
+        }
+    }
+    }
+    printf("\n Cost=%d",cost);
+}
+// driver code
+int main()
+{
+    struct node *Start=NULL;
+    struct Graph *G;
+    int i,v,e;
+    printf("enter vertex and edges");
+    scanf("%d %d",&v,&e);
+    G=create_graph(v,e);
+    for(i=0;i<G->V;i++)
+        insertion(&Start,i+1);
+    Prims(&Start,G);
+    return 0;
+}
+/*
+Input:
+enter vertex and edges 3
+6
+Enter the no. of nodes connected to V1 2
+enter the node no of v1 and weight2
+5
+enter the node no of v1 and weight 3
+2
+Enter the no. of nodes connected to V3 2
+enter the node no of v3 and weight1
+2
+enter the node no of v3 and weight 2
+2
+Enter the no. of nodes connected to V2 2
+enter the node no of v2 and weight 1
+5
+enter the node no of v2 and weight 3
+2
+Output: Cost: 4
+
+Time Complexity:O(V^2)
+
+*/