图的深度优先遍历和广度优先遍历

#include <iostream>
#include <cstdlib>
#include <set>
#include <vector>
#include <list>
#include <stack>
#include <queue>
using namespace std;

//BFS 广度优先遍历
void bfs(vector< list<int> >& adj_lists,int start_node)
{
 queue<int> not_yet_explored;
 set<int> discovered;
 
 //标记起始结点为已被发现，并将其放入队列中开始探索
 not_yet_explored.push(start_node);
 discovered.insert(start_node);
 
 while(!not_yet_explored.empty())
 {
  //获得一个新结点并依此作为基点进行探索
  int node_to_explore = not_yet_explored.front();
  not_yet_explored.pop();
  
  //检测该结点的所有边
  list<int>::iterator edges = adj_lists[node_to_explore].begin();
  for (;edges != adj_lists[node_to_explore].end();edges++)
  {
   if (discovered.count(*edges)==0)
   {
    //发现新结点将其加入队列
    discovered.insert(*edges);
    not_yet_explored.push(*edges);
    cout<<"Found "<<*edges<<" from "<<node_to_explore<<endl;
   }
  }
 }
}

//DFS 深度优先遍历
void dfs_helper(vector< list<int> >& adj_lists,set<int>& discovered,int node)
{
 //检测该结点的所有边
 list<int>::iterator edges = adj_lists[node].begin();
 for (;edges != adj_lists[node].end();edges++)
 {
  //检测某条边是否含有未发现的顶点
  if (discovered.count(*edges) == 0)
  {
   discovered.insert(*edges);
   cout<<"Found "<<*edges<<" from "<<node<<endl;
   dfs_helper(adj_lists,discovered,*edges);
  }
 }
}

void dfs(vector< list<int> >& adj_lists,int start_node)
{
 //标记起始结点为已被发现
 set<int> discovered;
 discovered.insert(start_node);
 dfs_helper(adj_lists,discovered,start_node);
}

int main()
{
 //初始化图信息
 vector< list<int> > g(7,list<int>());
 g[0].push_back(2);
 g[0].push_back(1);
 
 g[1].push_back(0);
 g[1].push_back(2);
 
 g[2].push_back(4);
 g[2].push_back(3);
 g[2].push_back(0);
 g[2].push_back(1);
 
 g[3].push_back(2);
 g[3].push_back(4);
 
 g[4].push_back(6);
 g[4].push_back(5);
 g[4].push_back(3);
 g[4].push_back(2);
 
 g[5].push_back(4);
 g[5].push_back(3);
 
 g[6].push_back(4);
 
 cout<<"BFS"<<endl;
 bfs(g,0);
 
 cout<<endl<<"DFS"<<endl;
 dfs(g,0);
 
 return 1;
}