short_path

Author: xiaomeng79

Makefile

@@ -10,7 +10,8 @@ fmt :
 	@gofmt -l -w ./
 
 
+
 .PHONY : test
 test :
 	@echo "测试代码"
-	go test -v ./...
+	@go test -v ./...

algorithms/graphs/README.md

@@ -16,4 +16,14 @@
 
 思想: 从顶点V出发，访问V之后依次访问v的各个未曾访问过的邻接点，然后分别从这些邻接点出发依次访问它们的邻接点
 
-队列
+队列
+
+### 最短路径
+
+#### 迪杰斯特拉(Dijkstra)
+
+[详解01](http://data.biancheng.net/view/46.html)
+
+[详解02](http://www.cnblogs.com/skywang12345/p/3711512.html)
+
+用于有向网中计算一个节点到其他节点的最短路径

algorithms/graphs/bfs-shortest-path/bfs_shortest_path.go

@@ -0,0 +1,30 @@
+package bfs_shortest_path
+
+import (
+	"github.com/xiaomeng79/go-algorithm/algorithms/graphs/bfs"
+	"github.com/xiaomeng79/go-algorithm/data-structures/graph"
+)
+
+func ShortestPath(g *graph.DirGraph, start graph.VertexId) (dist map[graph.VertexId]int) {
+	dist = make(map[graph.VertexId]int)
+	visited := make(map[graph.VertexId]bool)
+
+	getDist := func(v graph.VertexId) { //目标顶点
+		neighbours := g.GetNeighbours(v).VerticesIter()
+		visited[v] = true
+
+		for neighbour := range neighbours {
+
+			ok, _ := visited[neighbour]
+			if !ok {
+				dist[neighbour] = dist[v] + 1
+			}
+		}
+	}
+	bfs.Bfs(g, start, getDist)
+	return
+}
+
+func GetDist(g *graph.DirGraph, from, to graph.VertexId) int {
+	return ShortestPath(g, from)[to]
+}

algorithms/graphs/bfs-shortest-path/bfs_shortest_path_test.go

@@ -0,0 +1,20 @@
+package bfs_shortest_path
+
+import (
+	"github.com/stretchr/testify/assert"
+	"github.com/xiaomeng79/go-algorithm/data-structures/graph"
+	"testing"
+)
+
+func TestShortestPath(t *testing.T) {
+	h := graph.NewDirected()
+	for i := 0; i < 10; i++ {
+		h.AddVertex(graph.VertexId(i))
+	}
+
+	for i := 0; i < 9; i++ {
+		h.AddEdge(graph.VertexId(i), graph.VertexId(i+1), 1)
+	}
+
+	assert.Equal(t, 9, GetDist(h, graph.VertexId(0), graph.VertexId(9)))
+}