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krahets
2023-02-28 00:14:16 +08:00
parent bca1245c9b
commit 922c050246
5 changed files with 86 additions and 55 deletions
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chapter_graph/graph_operations.md
+19 -21
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@@ -1023,15 +1023,14 @@ comments: true
```go title="graph_adjacency_list.go"
/* 基于邻接表实现的无向图类 */
type graphAdjList struct {
// 邻接表，使用哈希表来代替链表，以提升删除边、删除顶点的效率
// 请注意，adjList 中的元素是 Vertex 对象
adjList map[vertex]map[vertex]struct{}
// 邻接表，key: 顶点，value：该顶点的所有邻接顶点
adjList map[Vertex][]Vertex
}
/* 构造方法 */
func newGraphAdjList(edges [][]vertex) *graphAdjList {
func newGraphAdjList(edges [][]Vertex) *graphAdjList {
g := &graphAdjList{
adjList: make(map[vertex]map[vertex]struct{}),
adjList: make(map[Vertex][]Vertex),
}
// 添加所有顶点和边
for _, edge := range edges {
@@ -1048,41 +1047,41 @@ comments: true
}
/* 添加边 */
func (g *graphAdjList) addEdge(vet1 vertex, vet2 vertex) {
func (g *graphAdjList) addEdge(vet1 Vertex, vet2 Vertex) {
_, ok1 := g.adjList[vet1]
_, ok2 := g.adjList[vet2]
if !ok1 || !ok2 || vet1 == vet2 {
panic("error")
}
// 添加边 vet1 - vet2, 添加匿名 struct{},
g.adjList[vet1][vet2] = struct{}{}
g.adjList[vet2][vet1] = struct{}{}
g.adjList[vet1] = append(g.adjList[vet1], vet2)
g.adjList[vet2] = append(g.adjList[vet2], vet1)
}
/* 删除边 */
func (g *graphAdjList) removeEdge(vet1 vertex, vet2 vertex) {
func (g *graphAdjList) removeEdge(vet1 Vertex, vet2 Vertex) {
_, ok1 := g.adjList[vet1]
_, ok2 := g.adjList[vet2]
if !ok1 || !ok2 || vet1 == vet2 {
panic("error")
}
// 删除边 vet1 - vet2, 借助 delete 来删除 map 中的键
delete(g.adjList[vet1], vet2)
delete(g.adjList[vet2], vet1)
// 删除边 vet1 - vet2
DeleteSliceElms(g.adjList[vet1], vet2)
DeleteSliceElms(g.adjList[vet2], vet1)
}
/* 添加顶点 */
func (g *graphAdjList) addVertex(vet vertex) {
func (g *graphAdjList) addVertex(vet Vertex) {
_, ok := g.adjList[vet]
if ok {
return
}
// 在邻接表中添加一个新链表
g.adjList[vet] = make(map[vertex]struct{})
g.adjList[vet] = make([]Vertex, 0)
}
/* 删除顶点 */
func (g *graphAdjList) removeVertex(vet vertex) {
func (g *graphAdjList) removeVertex(vet Vertex) {
_, ok := g.adjList[vet]
if !ok {
panic("error")
@@ -1090,9 +1089,8 @@ comments: true
// 在邻接表中删除顶点 vet 对应的链表
delete(g.adjList, vet)
// 遍历其它顶点的链表，删除所有包含 vet 的边
for _, set := range g.adjList {
// 操作
delete(set, vet)
for _, list := range g.adjList {
DeleteSliceElms(list, vet)
}
}
@@ -1101,9 +1099,9 @@ comments: true
var builder strings.Builder
fmt.Printf("邻接表 = \n")
for k, v := range g.adjList {
builder.WriteString("\t\t" + strconv.Itoa(k.val) + ": ")
for vet := range v {
builder.WriteString(strconv.Itoa(vet.val) + " ")
builder.WriteString("\t\t" + strconv.Itoa(k.Val) + ": ")
for _, vet := range v {
builder.WriteString(strconv.Itoa(vet.Val) + " ")
}
fmt.Println(builder.String())
builder.Reset()