mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-25 13:46:30 +08:00
e720aa2d24
* Sync recent changes to the revised Word. * Revised the preface chapter * Revised the introduction chapter * Revised the computation complexity chapter * Revised the chapter data structure * Revised the chapter array and linked list * Revised the chapter stack and queue * Revised the chapter hashing * Revised the chapter tree * Revised the chapter heap * Revised the chapter graph * Revised the chapter searching * Reivised the sorting chapter * Revised the divide and conquer chapter * Revised the chapter backtacking * Revised the DP chapter * Revised the greedy chapter * Revised the appendix chapter * Revised the preface chapter doubly * Revised the figures
124 lines
2.8 KiB
Dart
124 lines
2.8 KiB
Dart
/**
|
||
* File: graph_adjacency_list.dart
|
||
* Created Time: 2023-05-15
|
||
* Author: liuyuxin (gvenusleo@gmail.com)
|
||
*/
|
||
|
||
import '../utils/vertex.dart';
|
||
|
||
/* 基于邻接表实现的无向图类 */
|
||
class GraphAdjList {
|
||
// 邻接表，key：顶点，value：该顶点的所有邻接顶点
|
||
Map<Vertex, List<Vertex>> adjList = {};
|
||
|
||
/* 构造方法 */
|
||
GraphAdjList(List<List<Vertex>> edges) {
|
||
for (List<Vertex> edge in edges) {
|
||
addVertex(edge[0]);
|
||
addVertex(edge[1]);
|
||
addEdge(edge[0], edge[1]);
|
||
}
|
||
}
|
||
|
||
/* 获取顶点数量 */
|
||
int size() {
|
||
return adjList.length;
|
||
}
|
||
|
||
/* 添加边 */
|
||
void addEdge(Vertex vet1, Vertex vet2) {
|
||
if (!adjList.containsKey(vet1) ||
|
||
!adjList.containsKey(vet2) ||
|
||
vet1 == vet2) {
|
||
throw ArgumentError;
|
||
}
|
||
// 添加边 vet1 - vet2
|
||
adjList[vet1]!.add(vet2);
|
||
adjList[vet2]!.add(vet1);
|
||
}
|
||
|
||
/* 删除边 */
|
||
void removeEdge(Vertex vet1, Vertex vet2) {
|
||
if (!adjList.containsKey(vet1) ||
|
||
!adjList.containsKey(vet2) ||
|
||
vet1 == vet2) {
|
||
throw ArgumentError;
|
||
}
|
||
// 删除边 vet1 - vet2
|
||
adjList[vet1]!.remove(vet2);
|
||
adjList[vet2]!.remove(vet1);
|
||
}
|
||
|
||
/* 添加顶点 */
|
||
void addVertex(Vertex vet) {
|
||
if (adjList.containsKey(vet)) return;
|
||
// 在邻接表中添加一个新链表
|
||
adjList[vet] = [];
|
||
}
|
||
|
||
/* 删除顶点 */
|
||
void removeVertex(Vertex vet) {
|
||
if (!adjList.containsKey(vet)) {
|
||
throw ArgumentError;
|
||
}
|
||
// 在邻接表中删除顶点 vet 对应的链表
|
||
adjList.remove(vet);
|
||
// 遍历其他顶点的链表，删除所有包含 vet 的边
|
||
adjList.forEach((key, value) {
|
||
value.remove(vet);
|
||
});
|
||
}
|
||
|
||
/* 打印邻接表 */
|
||
void printAdjList() {
|
||
print("邻接表 =");
|
||
adjList.forEach((key, value) {
|
||
List<int> tmp = [];
|
||
for (Vertex vertex in value) {
|
||
tmp.add(vertex.val);
|
||
}
|
||
print("${key.val}: $tmp,");
|
||
});
|
||
}
|
||
}
|
||
|
||
/* Driver Code */
|
||
void main() {
|
||
/* 初始化无向图 */
|
||
List<Vertex> v = Vertex.valsToVets([1, 3, 2, 5, 4]);
|
||
List<List<Vertex>> edges = [
|
||
[v[0], v[1]],
|
||
[v[0], v[3]],
|
||
[v[1], v[2]],
|
||
[v[2], v[3]],
|
||
[v[2], v[4]],
|
||
[v[3], v[4]],
|
||
];
|
||
GraphAdjList graph = GraphAdjList(edges);
|
||
print("\n初始化后，图为");
|
||
graph.printAdjList();
|
||
|
||
/* 添加边 */
|
||
// 顶点 1, 2 即 v[0], v[2]
|
||
graph.addEdge(v[0], v[2]);
|
||
print("\n添加边 1-2 后，图为");
|
||
graph.printAdjList();
|
||
|
||
/* 删除边 */
|
||
// 顶点 1, 3 即 v[0], v[1]
|
||
graph.removeEdge(v[0], v[1]);
|
||
print("\n删除边 1-3 后，图为");
|
||
graph.printAdjList();
|
||
|
||
/* 添加顶点 */
|
||
Vertex v5 = Vertex(6);
|
||
graph.addVertex(v5);
|
||
print("\n添加顶点 6 后，图为");
|
||
graph.printAdjList();
|
||
|
||
/* 删除顶点 */
|
||
// 顶点 3 即 v[1]
|
||
graph.removeVertex(v[1]);
|
||
print("\n删除顶点 3 后，图为");
|
||
graph.printAdjList();
|
||
}
|