该算法可以求任意两点之间的最短路,并且输出路径点。
#include <iostream>
#include <cstdio>
#include <vector>
#define Min(x,y) ( (x) < (y) ? (x) : (y) )
using namespace std;
const int maxn = 205;
const int INF = 0x3f3f3f3f;
int path[maxn];
struct Node
{
int vex,weight;
Node(int _vex = 0,int _weight = 0) : vex(_vex),weight(_weight){}
};
vector<Node> G[maxn];
bool intree[maxn];//判断是否已经加入最短路集合
int mindist[maxn],n,m;
void Init()
{
for(int i = 0 ; i < maxn ; ++i){
G[i].clear();
mindist[i] = INF; //初始化为最大值
intree[i] = false;
}
}
int Dijkstra(int s,int e)
{
int ans = 0;
int vex,addNode,tempMin;//加入集合F中的节点
intree[s] = true;//加入生成树
for(unsigned int i = 0 ; i < G[s].size() ; ++i){
vex = G[s][i].vex;
mindist[vex] = Min(mindist[vex],G[s][i].weight);
path[vex] = s;//vex点是由s点更新的
}//寻找与当前节点相连的最小点
mindist[s] = 0;//s到s的距离为自身
for(int nodeNum = 1 ; nodeNum <= n - 1 ; ++nodeNum){//找到那个点把他加入
tempMin = INF;
for(int i = 0 ; i < n ; ++i){//编号0-n-1
if(intree[i] == false && mindist[i] < tempMin){
tempMin = mindist[i];
addNode = i;
}
}
intree[addNode] = true;//addNode 加入集合F
for(unsigned int i = 0 ; i < G[addNode].size() ; ++i){//找到这个点的相邻点并且更新所有值
vex = G[addNode][i].vex;
if(intree[vex] == false && mindist[addNode] + G[addNode][i].weight < mindist[vex])//
mindist[vex] = mindist[addNode] + G[addNode][i].weight;
path[vex] = addNode;//更新之后的路径点
}
}
return mindist[e];
}
void p()
{
int tmp;
while(!si.empty())si.pop();
si.push(e);
int ee = e;
while(s!=e)
{
tmp=path[e];
si.push(tmp);
e= tmp;
}
if(!outfile){
cout << "Unable to open otfile";
exit(1);
}
outfile<<s<<"到"<<ee<<"所经历的点为:"<<endl;
int cnt=0;
while(!si.empty())
{
cout<<' '<<si.top();
si.pop();
}
cout<<endl;
}
int main()
{
int v1,v2,weight,s,e;
while(scanf("%d%d",&n,&m) != EOF)//n个节点,m条边
{
Init();//初始化函数
for(int i = 0 ; i < m ; i++){
scanf("%d%d%d",&v1,&v2,&weight);//无向图V1与V2相连,所以V2与V1相连,weight为两点之间的长度
G[v1].push_back(Node(v2,weight));
G[v2].push_back(Node(v1,weight));
}
scanf("%d%d",&s,&e);//s为起始点,e为终点
int ans = Dijkstra(s,e);
if(ans == INF)
printf("%d\n",-1);
else
printf("%d\n",ans);
}
return 0;
}