hello-algo/codes/cpp/chapter_graph/graph_dfs.cpp

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/**
* File: graph_dfs.cpp
* Created Time: 2023-03-02
* Author: Krahets (krahets@163.com)
*/
#include "../include/include.hpp"
#include "./graph_adjacency_list.cpp"
/* 深度优先遍历 DFS 辅助函数 */
void dfs(GraphAdjList& graph, unordered_set<Vertex*>& visited, vector<Vertex*>& res, Vertex* vet) {
res.push_back(vet); // 记录访问顶点
visited.emplace(vet); // 标记该顶点已被访问
// 遍历该顶点的所有邻接顶点
for (Vertex* adjVet : graph.adjList[vet]) {
if (visited.count(adjVet))
continue; // 跳过已被访问过的顶点
// 递归访问邻接顶点
dfs(graph, visited, res, adjVet);
}
}
/* 深度优先遍历 DFS */
// 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*> graphDFS(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;
dfs(graph, visited, res, startVet);
return res;
}
/* Driver Code */
int main() {
/* 初始化无向图 */
vector<Vertex*> v = valsToVets(vector<int> { 0, 1, 2, 3, 4, 5, 6 });
vector<vector<Vertex*>> edges = { { v[0], v[1] }, { v[0], v[3] }, { v[1], v[2] },
{ v[2], v[5] }, { v[4], v[5] }, { v[5], v[6] } };
GraphAdjList graph(edges);
cout << "\n初始化后,图为" << endl;
graph.print();
/* 深度优先遍历 DFS */
vector<Vertex*> res = graphDFS(graph, v[0]);
cout << "\n深度优先遍历DFS顶点序列为" << endl;
PrintUtil::printVector(vetsToVals(res));
// 释放内存
for (Vertex *vet : v) {
delete vet;
}
return 0;
}