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myselfshravan
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readme up
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‎11.dijkstras.c

Lines changed: 69 additions & 102 deletions
Original file line numberDiff line numberDiff line change
@@ -1,109 +1,76 @@
1-
// C program for Dijkstra's single source shortest path
2-
// algorithm. The program is for adjacency matrix
3-
// representation of the graph
4-
5-
#include <limits.h>
6-
#include <stdbool.h>
71
#include <stdio.h>
8-
#include <time.h>
9-
// Number of vertices in the graph
10-
#define V 9
11-
12-
// A utility function to find the vertex with minimum
13-
// distance value, from the set of vertices not yet included
14-
// in shortest path tree
15-
int minDistance(int dist[], bool sptSet[])
16-
{
17-
// Initialize min value
18-
int min = INT_MAX, min_index;
19-
20-
for (int v = 0; v < V; v++)
21-
if (sptSet[v] == false && dist[v] <= min)
22-
min = dist[v], min_index = v;
23-
24-
return min_index;
25-
}
26-
27-
// A utility function to print the constructed distance
28-
// array
29-
void printSolution(int dist[])
2+
#define INFINITY 9999
3+
#define MAX 10
4+
void dijkstra(int G[MAX][MAX], int n, int startnode);
5+
int main()
306
{
31-
printf("Vertex \t\t Distance from Source\n");
32-
for (int i = 0; i < V; i++)
33-
printf("%d \t\t\t\t %d\n", i, dist[i]);
7+
int G[MAX][MAX], i, j, n, u;
8+
printf("Enter no. of vertices: ");
9+
scanf("%d", &n);
10+
printf("\nEnter the adjacency matrix:\n");
11+
for (i = 0; i < n; i++)
12+
for (j = 0; j < n; j++)
13+
scanf("%d", &G[i][j]);
14+
printf("\nEnter the starting node: ");
15+
scanf("%d", &u);
16+
dijkstra(G, n, u);
17+
return 0;
3418
}
35-
36-
// Function that implements Dijkstra's single source
37-
// shortest path algorithm for a graph represented using
38-
// adjacency matrix representation
39-
void dijkstra(int graph[V][V], int src)
19+
void dijkstra(int G[MAX][MAX], int n, int startnode)
4020
{
41-
int dist[V]; // The output array. dist[i] will hold the
42-
// shortest
43-
// distance from src to i
44-
45-
bool sptSet[V]; // sptSet[i] will be true if vertex i is
46-
// included in shortest
47-
// path tree or shortest distance from src to i is
48-
// finalized
49-
50-
// Initialize all distances as INFINITE and stpSet[] as
51-
// false
52-
for (int i = 0; i < V; i++)
53-
dist[i] = INT_MAX, sptSet[i] = false;
54-
55-
// Distance of source vertex from itself is always 0
56-
dist[src] = 0;
57-
58-
// Find shortest path for all vertices
59-
for (int count = 0; count < V - 1; count++)
21+
int cost[MAX][MAX], distance[MAX], pred[MAX];
22+
int visited[MAX], count, mindistance, nextnode, i, j;
23+
// pred[] stores the predecessor of each node
24+
// count gives the number of nodes seen so far
25+
// create the cost matrix
26+
for (i = 0; i < n; i++)
27+
for (j = 0; j < n; j++)
28+
if (G[i][j] == 0)
29+
cost[i][j] = INFINITY;
30+
else
31+
cost[i][j] = G[i][j];
32+
// initialize pred[],distance[] and visited[]
33+
for (i = 0; i < n; i++)
6034
{
61-
// Pick the minimum distance vertex from the set of
62-
// vertices not yet processed. u is always equal to
63-
// src in the first iteration.
64-
int u = minDistance(dist, sptSet);
65-
66-
// Mark the picked vertex as processed
67-
sptSet[u] = true;
68-
69-
// Update dist value of the adjacent vertices of the
70-
// picked vertex.
71-
for (int v = 0; v < V; v++)
72-
73-
// Update dist[v] only if is not in sptSet,
74-
// there is an edge from u to v, and total
75-
// weight of path from src to v through u is
76-
// smaller than current value of dist[v]
77-
if (!sptSet[v] && graph[u][v] && dist[u] != INT_MAX && dist[u] + graph[u][v] < dist[v])
78-
dist[v] = dist[u] + graph[u][v];
35+
distance[i] = cost[startnode][i];
36+
pred[i] = startnode;
37+
visited[i] = 0;
7938
}
80-
81-
// print the constructed distance array
82-
printSolution(dist);
83-
}
84-
85-
// driver's code
86-
int main()
87-
{
88-
/* Let us create the example graph discussed above */
89-
int graph[V][V] = {{0, 4, 0, 0, 0, 0, 0, 8, 0},
90-
{4, 0, 8, 0, 0, 0, 0, 11, 0},
91-
{0, 8, 0, 7, 0, 4, 0, 0, 2},
92-
{0, 0, 7, 0, 9, 14, 0, 0, 0},
93-
{0, 0, 0, 9, 0, 10, 0, 0, 0},
94-
{0, 0, 4, 14, 10, 0, 2, 0, 0},
95-
{0, 0, 0, 0, 0, 2, 0, 1, 6},
96-
{8, 11, 0, 0, 0, 0, 1, 0, 7},
97-
{0, 0, 2, 0, 0, 0, 6, 7, 0}};
98-
99-
// Function call
100-
clock_t start, end;
101-
float cpu_time_used;
102-
start = clock();
103-
dijkstra(graph, 0);
104-
end = clock();
105-
cpu_time_used = ((float)(end - start)) / CLOCKS_PER_SEC;
106-
printf("\nTime complexity is: %f", cpu_time_used);
107-
108-
return 0;
39+
distance[startnode] = 0;
40+
visited[startnode] = 1;
41+
count = 1;
42+
while (count < n - 1)
43+
{
44+
mindistance = INFINITY;
45+
// nextnode gives the node at minimum distance
46+
for (i = 0; i < n; i++)
47+
if (distance[i] < mindistance && !visited[i])
48+
{
49+
mindistance = distance[i];
50+
nextnode = i;
51+
}
52+
// check if a better path exists through nextnode
53+
visited[nextnode] = 1;
54+
for (i = 0; i < n; i++)
55+
if (!visited[i])
56+
if (mindistance + cost[nextnode][i] < distance[i])
57+
{
58+
distance[i] = mindistance + cost[nextnode][i];
59+
pred[i] = nextnode;
60+
}
61+
count++;
62+
}
63+
// print the path and distance of each node
64+
for (i = 0; i < n; i++)
65+
if (i != startnode)
66+
{
67+
printf("\nDistance of node%d= %d", i, distance[i]);
68+
printf("\nPath= %d", i);
69+
j = i;
70+
do
71+
{
72+
j = pred[j];
73+
printf("<-%d", j);
74+
} while (j != startnode);
75+
}
10976
}

‎12.Travelling_Salesman.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -65,7 +65,7 @@ void put()
6565
int main()
6666
{
6767
get();
68-
printf("\n\nThe Path is:\n\n");
68+
printf("\n\nThe Path is: ");
6969
mincost(0);
7070
put();
7171
return 0;

‎README.md

Lines changed: 19 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -211,15 +211,15 @@ Total cost of spanning tree = 8
211211
Example 1:
212212

213213
```bash
214-
Enter no. of vertices: 5
214+
Kruskal's algorithm in C
215+
========================
216+
Enter the no. of vertices: 5
215217
Enter the cost adjacency matrix:
216-
217218
0 1 2 0 1
218219
1 0 3 0 1
219220
2 3 0 6 5
220221
0 0 6 0 0
221222
1 1 5 0 0
222-
223223
The edges of Minimum Cost Spanning Tree are
224224
1 edge (1,2) = 1
225225
2 edge (1,5) = 1
@@ -255,22 +255,21 @@ Minimum cost = 13
255255
```bash
256256
Enter no. of vertices: 5
257257
Enter the adjacency matrix:
258-
0 10 0 30 100
259-
10 0 50 0 0
260-
0 50 0 20 10
261-
30 0 20 0 60
262-
100 0 10 60 0
263-
264-
Enter the starting node:0
265-
266-
Distance of node1=10
267-
Path=1<-0
268-
Distance of node2=50
269-
Path=2<-3<-0
270-
Distance of node3=30
271-
Path=3<-0
272-
Distance of node4=60
273-
Path=4<-2<-3<-0
258+
0 1 0 3 9
259+
1 0 5 0 0
260+
0 5 0 2 1
261+
3 0 2 0 6
262+
9 0 1 6 0
263+
264+
Enter the starting node: 0
265+
Distance of node1= 1
266+
Path= 1<-0
267+
Distance of node2= 5
268+
Path= 2<-3<-0
269+
Distance of node3= 3
270+
Path= 3<-0
271+
Distance of node4= 6
272+
Path= 4<-2<-3<-0
274273
```
275274

276275
## Travelling Salesman Input/Output:
@@ -301,9 +300,7 @@ The cost list is:
301300
99 10 99 6 99 99
302301
10 99 5 99 99 99
303302

304-
The Path is:
305-
306-
1->6->3->4->5->2->1
303+
The Path is: 1->6->3->4->5->2->1
307304

308305
Minimum cost: 46
309306
```

‎lab-manual/11.dijkstras.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@ int main()
1111
for (i = 0; i < n; i++)
1212
for (j = 0; j < n; j++)
1313
scanf("%d", &G[i][j]);
14-
printf("\nEnter the starting node:");
14+
printf("\nEnter the starting node: ");
1515
scanf("%d", &u);
1616
dijkstra(G, n, u);
1717
return 0;

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