Dijkstra+DFS模板（PAT1030 Travel Plan (30分)）

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
const int INF = 10000000;

int dis[501][501];
int cost[501][501];

int dest[501];
bool visited[501] = {false};
vector<int> paths[501];

int N,M,S,T;
 
void Dij(){
	fill(dest,dest+501,INF);
	dest[S] = 0;
	//注意不能将起点设为访问过 
	for(int i=0; i<N; ++i){
		int u = -1;
		int mmin = INF;
		for(int i=0; i<N; ++i){
			if(!visited[i] && dest[i] < mmin){
				u = i;
				mmin = dest[i];
			}
		}
		if(u==-1)
			return;
		visited[u] = true;
		for(int v = 0; v < N; ++v){
			if(!visited[v] && dis[u][v] != INF){
				if(dest[u] + dis[u][v] < dest[v]){
					dest[v] = dest[u] + dis[u][v];
					paths[v].clear();
					paths[v].push_back(u);
				}else if(dest[u] + dis[u][v] == dest[v]){
					paths[v].push_back(u);
				}
			}
		}
	}
}

vector<int> end_path;
vector<int> temp_path;
int end_cost = INF;



void DFS(int v){
	temp_path.push_back(v);
	if(v == S){
		int temp_cost = 0;
		for(int i = temp_path.size()-1; i>0; --i)
			temp_cost += cost[temp_path[i]][temp_path[i-1]];
		if(temp_cost < end_cost){
			end_cost = temp_cost;
			end_path = temp_path;
		}
		
		temp_path.pop_back();
		return;   //******************************
	}
	for(int i=0; i<paths[v].size(); ++i){
		DFS(paths[v][i]);
	}
	temp_path.pop_back();
}



 
int main(){
	cin>>N>>M>>S>>T;
	for(int i = 0; i<N; ++i)
		for(int j=0; j<N; ++j)
			dis[i][j] = INF;
	for(int i=0; i<M; ++i){
			int s,e,d,c;
			cin>>s>>e>>d>>c;
			dis[s][e] = d;
			dis[e][s] = d;
			cost[s][e] = c;
			cost[e][s] = c;
		}
	Dij();
	DFS(T);
	reverse(end_path.begin(),end_path.end());
	for(auto v: end_path)
		cout<<v<<" ";
	cout<<dest[T]<<" "<<end_cost;
	return 0;
}