Fix bug in shortest path implementation

gsliepen · Jan 22, 2024 · 7eeb292 · 7eeb292
1 parent 3990f75
commit 7eeb292
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/src/graph.c b/src/graph.c
@@ -141,6 +141,7 @@ void sssp_bfs(void) {
 	myself->prevedge = NULL;
 	myself->via = myself;
 	myself->distance = 0;
+	myself->weighted_distance = 0;
 	list_insert_head(todo_list, myself);
 
 	/* Loop while todo_list is filled */
@@ -178,14 +179,15 @@ void sssp_bfs(void) {
 
 			if(e->to->status.visited
 			                && (!e->to->status.indirect || indirect)
-			                && (e->to->distance != n->distance + 1 || e->weight >= e->to->prevedge->weight)) {
+			                && (e->to->distance != n->distance + 1 || e->to->weighted_distance <= n->weighted_distance + e->weight)) {
 				continue;
 			}
 
 			// Only update nexthop if it doesn't increase the path length
 
-			if(!e->to->status.visited || (e->to->distance == n->distance + 1 && e->weight < e->to->prevedge->weight)) {
+			if(!e->to->status.visited || (e->to->distance == n->distance + 1 && e->to->weighted_distance > n->weighted_distance + e->weight)) {
 				e->to->nexthop = (n->nexthop == myself) ? e->to : n->nexthop;
+				e->to->weighted_distance = n->weighted_distance + e->weight;
 			}
 
 			e->to->status.visited = true;

diff --git a/src/node.h b/src/node.h
@@ -76,6 +76,7 @@ typedef struct node_t {
 	compression_level_t outcompression;     /* Compression level, 0 = no compression */
 
 	int distance;
+	int weighted_distance;
 	struct node_t *nexthop;                 /* nearest node from us to him */
 	struct edge_t *prevedge;                /* nearest node from him to us */
 	struct node_t *via;                     /* next hop for UDP packets */