mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-28 12:16:28 +08:00
59 lines
2 KiB
C++
59 lines
2 KiB
C++
/**
|
||
* File: graph_bfs.cpp
|
||
* Created Time: 2023-03-02
|
||
* Author: Krahets (krahets@163.com)
|
||
*/
|
||
|
||
#include "../utils/common.hpp"
|
||
#include "./graph_adjacency_list.cpp"
|
||
|
||
/* 广度优先遍历 BFS */
|
||
// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
|
||
vector<Vertex *> graphBFS(GraphAdjList &graph, Vertex *startVet) {
|
||
// 顶点遍历序列
|
||
vector<Vertex *> res;
|
||
// 哈希表，用于记录已被访问过的顶点
|
||
unordered_set<Vertex *> visited = {startVet};
|
||
// 队列用于实现 BFS
|
||
queue<Vertex *> que;
|
||
que.push(startVet);
|
||
// 以顶点 vet 为起点，循环直至访问完所有顶点
|
||
while (!que.empty()) {
|
||
Vertex *vet = que.front();
|
||
que.pop(); // 队首顶点出队
|
||
res.push_back(vet); // 记录访问顶点
|
||
// 遍历该顶点的所有邻接顶点
|
||
for (auto adjVet : graph.adjList[vet]) {
|
||
if (visited.count(adjVet))
|
||
continue; // 跳过已被访问过的顶点
|
||
que.push(adjVet); // 只入队未访问的顶点
|
||
visited.emplace(adjVet); // 标记该顶点已被访问
|
||
}
|
||
}
|
||
// 返回顶点遍历序列
|
||
return res;
|
||
}
|
||
|
||
/* Driver Code */
|
||
int main() {
|
||
/* 初始化无向图 */
|
||
vector<Vertex *> v = valsToVets({0, 1, 2, 3, 4, 5, 6, 7, 8, 9});
|
||
vector<vector<Vertex *>> edges = {{v[0], v[1]}, {v[0], v[3]}, {v[1], v[2]}, {v[1], v[4]},
|
||
{v[2], v[5]}, {v[3], v[4]}, {v[3], v[6]}, {v[4], v[5]},
|
||
{v[4], v[7]}, {v[5], v[8]}, {v[6], v[7]}, {v[7], v[8]}};
|
||
GraphAdjList graph(edges);
|
||
cout << "\n初始化后，图为\\n";
|
||
graph.print();
|
||
|
||
/* 广度优先遍历 BFS */
|
||
vector<Vertex *> res = graphBFS(graph, v[0]);
|
||
cout << "\n广度优先遍历（BFS）顶点序列为" << endl;
|
||
printVector(vetsToVals(res));
|
||
|
||
// 释放内存
|
||
for (Vertex *vet : v) {
|
||
delete vet;
|
||
}
|
||
|
||
return 0;
|
||
}
|