1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
/******************************************
Breadth First Search
Computes single-source distances for
unweighted graphs
******************************************/
#include <neatogen/bfs.h>
#include <util/list.h>
void bfs(int vertex, vtx_data *graph, int n, DistType *dist) {
DistType closestDist = INT_MAX;
// initial distances with edge weights
for (int i = 0; i < n; i++)
dist[i] = -1;
dist[vertex] = 0;
LIST(int) Q = {0};
LIST_PUSH_BACK(&Q, vertex);
while (!LIST_IS_EMPTY(&Q)) {
const int closestVertex = LIST_POP_FRONT(&Q);
closestDist = dist[closestVertex];
for (size_t i = 1; i < graph[closestVertex].nedges; i++) {
const int neighbor = graph[closestVertex].edges[i];
if (dist[neighbor] < -0.5) { // first time to reach neighbor
const DistType bump = graph[0].ewgts == NULL
? 1
: (DistType)graph[closestVertex].ewgts[i];
dist[neighbor] = closestDist + bump;
LIST_PUSH_BACK(&Q, neighbor);
}
}
}
// for dealing with disconnected graphs
for (int i = 0; i < n; i++)
if (dist[i] < -0.5) // `i` is not connected to `vertex`
dist[i] = closestDist + 10;
LIST_FREE(&Q);
}
|
