add edge weighted digraph

Author: shellfly

README.md

@@ -72,6 +72,8 @@ To test each algorithm(data structure), instead of running the file directly, yo
     * [LazyPrimMST](lazy_prim_mst.go)
     * [PrimMST](prim_mst.go)
     * [KruskalMST](kruskal_mst.go)
+  * Shortest Paths
+    * [EdgeWeightedDigraph](edge_weighted_digraph.go)
 
 * 5 STRING
 

cmd/edge-weighted-digraph/main.go

@@ -0,0 +1,36 @@
+/******************************************************************************
+ *  Execution:    go run cmd/edge-weighted-graph/main.go filename.txt
+ *  Data files:   https://algs4.cs.princeton.edu/43mst/tinyEWG.txt
+ *                https://algs4.cs.princeton.edu/43mst/mediumEWG.txt
+ *                https://algs4.cs.princeton.edu/43mst/largeEWG.txt
+ *
+ *  An edge-weighted undirected graph, implemented using adjacency lists.
+ *  Parallel edges and self-loops are permitted.
+ *
+ *  % go run cmd/edge-weighted-graph/main.go tinyEWG.txt
+ *  8 16
+ *  0: 6-0 0.58000  0-2 0.26000  0-4 0.38000  0-7 0.16000
+ *  1: 1-3 0.29000  1-2 0.36000  1-7 0.19000  1-5 0.32000
+ *  2: 6-2 0.40000  2-7 0.34000  1-2 0.36000  0-2 0.26000  2-3 0.17000
+ *  3: 3-6 0.52000  1-3 0.29000  2-3 0.17000
+ *  4: 6-4 0.93000  0-4 0.38000  4-7 0.37000  4-5 0.35000
+ *  5: 1-5 0.32000  5-7 0.28000  4-5 0.35000
+ *  6: 6-4 0.93000  6-0 0.58000  3-6 0.52000  6-2 0.40000
+ *  7: 2-7 0.34000  1-7 0.19000  0-7 0.16000  5-7 0.28000  4-7 0.37000
+ *
+ ******************************************************************************/
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/shellfly/algo"
+	"github.com/shellfly/algo/stdin"
+)
+
+func main() {
+	graph := algo.NewEdgeWeightedGraph(stdin.NewIn(os.Args[1]))
+	fmt.Println(graph)
+}

directed_edge.go

@@ -0,0 +1,46 @@
+package algo
+
+import "fmt"
+
+// DirectedEdge is a ADT for DirectedEdgeWeightedGraph
+type DirectedEdge struct {
+	v, w   int
+	weight float32
+}
+
+// NewDirectedEdge ...
+func NewDirectedEdge(v, w int, weight float32) *DirectedEdge {
+	return &DirectedEdge{v, w, weight}
+}
+
+// Weight ...
+func (e *DirectedEdge) Weight() float32 {
+	return e.weight
+}
+
+// From ...
+func (e *DirectedEdge) From() int {
+	return e.v
+}
+
+// To ...
+func (e *DirectedEdge) To() int {
+	return e.w
+}
+
+// String ...
+func (e *DirectedEdge) String() string {
+	return fmt.Sprintf("%d-%d %.5f", e.v, e.w, e.weight)
+}
+
+// CompareTo implements PQItem interface
+func (e *DirectedEdge) CompareTo(other interface{}) int {
+	ee := other.(*DirectedEdge)
+	if e.weight > ee.weight {
+		return 1
+	} else if e.weight < ee.weight {
+		return -1
+	} else {
+		return 0
+	}
+}

edge_weighted_digraph.go

@@ -0,0 +1,85 @@
+package algo
+
+import (
+	"fmt"
+
+	"github.com/shellfly/algo/stdin"
+)
+
+// EdgeWeightedDigraph ...
+type EdgeWeightedDigraph struct {
+	v, e int
+	adj  []*Bag
+}
+
+// NewEdgeWeightedDigraph ...
+func NewEdgeWeightedDigraph(in *stdin.In) *EdgeWeightedDigraph {
+	v := in.ReadInt()
+	adj := make([]*Bag, v)
+	for i := 0; i < v; i++ {
+		adj[i] = NewBag()
+	}
+	g := &EdgeWeightedDigraph{v: v, e: 0, adj: adj}
+	e := in.ReadInt()
+	for i := 0; i < e; i++ {
+		v, w, weight := in.ReadInt(), in.ReadInt(), in.ReadFloat32()
+		g.AddEdge(NewDirectedEdge(v, w, weight))
+	}
+	return g
+}
+
+// NewEdgeWeightedDigraphV ...
+func NewEdgeWeightedDigraphV(v int) *EdgeWeightedDigraph {
+	adj := make([]*Bag, v)
+	for i := 0; i < v; i++ {
+		adj[i] = NewBag()
+	}
+	return &EdgeWeightedDigraph{v: v, e: 0, adj: adj}
+}
+
+// V ...
+func (g *EdgeWeightedDigraph) V() int {
+	return g.v
+}
+
+// E ...
+func (g *EdgeWeightedDigraph) E() int {
+	return g.e
+}
+
+// AddEdge ...
+func (g *EdgeWeightedDigraph) AddEdge(e *DirectedEdge) {
+	g.adj[e.From()].Add(e.To())
+	g.e++
+}
+
+// Adj ...
+func (g *EdgeWeightedDigraph) Adj(v int) []*DirectedEdge {
+	var items []*DirectedEdge
+	for _, item := range g.adj[v].Slice() {
+		items = append(items, item.(*DirectedEdge))
+	}
+	return items
+}
+
+// Edges ...
+func (g *EdgeWeightedDigraph) Edges() (edges []*DirectedEdge) {
+	for v := 0; v < g.v; v++ {
+		for _, e := range g.Adj(v) {
+			edges = append(edges, e)
+		}
+	}
+	return
+}
+
+func (g *EdgeWeightedDigraph) String() string {
+	s := fmt.Sprintf("%d vertices, %d edges\n", g.v, g.e)
+	for i := 0; i < g.v; i++ {
+		var adjs string
+		for _, e := range g.Adj(i) {
+			adjs = fmt.Sprintf("%s %s ", adjs, e)
+		}
+		s += fmt.Sprintf("%d: %s\n", i, adjs)
+	}
+	return s
+}