search: add time complexity notes

gonum · Jun 8, 2015 · 83cfacf · 83cfacf
1 parent 2babe18
commit 83cfacf
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diff --git a/search/bellman_ford_moore.go b/search/bellman_ford_moore.go
@@ -9,6 +9,8 @@ import "github.com/gonum/graph"
 // BellmanFordFrom returns a shortest-path tree for a shortest path from u to all nodes in
 // the graph g, or false indicating that a negative cycle exists in the graph. If weight
 // is nil and the graph does not implement graph.Coster, UniformCost is used.
+//
+// The time complexity of BellmanFordFrom is O(|V|.|E|).
 func BellmanFordFrom(u graph.Node, g graph.Graph, weight graph.CostFunc) (path Shortest, ok bool) {
 	if !g.NodeExists(u) {
 		return Shortest{from: u}, true

diff --git a/search/dijkstra.go b/search/dijkstra.go
@@ -15,6 +15,8 @@ import (
 // DijkstraFrom returns a shortest-path tree for a shortest path from u to all nodes in
 // the graph g. If weight is nil and the graph does not implement graph.Coster, UniformCost
 // is used. DijkstraFrom will panic if g has a u-reachable negative edge weight.
+//
+// The time complexity of DijkstrFrom is O(|E|+|V|.log|V|).
 func DijkstraFrom(u graph.Node, g graph.Graph, weight graph.CostFunc) Shortest {
 	if !g.NodeExists(u) {
 		return Shortest{from: u}
@@ -73,6 +75,8 @@ func DijkstraFrom(u graph.Node, g graph.Graph, weight graph.CostFunc) Shortest {
 // DijkstraAllPaths returns a shortest-path tree for shortest paths in the graph g.
 // If weight is nil and the graph does not implement graph.Coster, UniformCost is used.
 // DijkstraAllPaths will panic if g has a negative edge weight.
+//
+// The time complexity of DijkstrAllPaths is O(|V|.|E|+|V|^2.log|V|).
 func DijkstraAllPaths(g graph.Graph, weight graph.CostFunc) (paths ShortestPaths) {
 	var (
 		from   = g.Neighbors

diff --git a/search/floydwarshall.go b/search/floydwarshall.go
@@ -14,6 +14,8 @@ import (
 // FloydWarshall returns a shortest-path tree for the graph g or false indicating
 // that a negative cycle exists in the graph. If weight is nil and the graph does not
 // implement graph.Coster, UniformCost is used.
+//
+// The time complexity of FloydWarshall is O(|V|^3).
 func FloydWarshall(g graph.Graph, weight graph.CostFunc) (paths ShortestPaths, ok bool) {
 	var (
 		from   = g.Neighbors

diff --git a/search/johnson_apsp.go b/search/johnson_apsp.go
@@ -14,6 +14,8 @@ import (
 
 // JohnsonAllPaths returns a shortest-path tree for shortest paths in the graph g.
 // If weight is nil and the graph does not implement graph.Coster, UniformCost is used.
+//
+// The time complexity of JohnsonAllPaths is O(|V|.|E|+|V|^2.log|V|).
 func JohnsonAllPaths(g graph.Graph, weight graph.CostFunc) (paths ShortestPaths, ok bool) {
 	jg := johnsonWeightAdjuster{
 		g:      g,