The prim and Dijkstra algorithms mainly have different meanings on the d array. For the d array of prim, d[i] is the distance from the i node to the minimum spanning tree combination, while Dijkstra's d array is the distance from the i node to the target node s .
The shortest path and use path and search array to record path node information
#include <bits/stdc++.h>
#define maxv 1000
#define INF 99999
using namespace std;
int n,m,s;/*n个顶点、m条边、s为起点*/
int path[maxv];/*一个并查集数组*/
int G[maxv][maxv];
int d[maxv];/*d[i]代表着第i个节点到目标节点s的距离*/
bool vis[maxv]={
false};
int findfater(int x){
int index=x;
int temp[100];
int top=0;
temp[top++]=x;
while(path[x]!=x){
//cout<<x<<' ';
x=path[x];
temp[top++]=x;
}
//temp[top++]=x;
for(int i=top-1;i>=0;i--){
if(d[index]==INF){
cout<<s<<" 不可达 "<<i;
break;
}
else if(d[index]==0){
cout<<"自身节点";
break;
}
if(i!=0){
cout<<temp[i]<<"-->";
}else{
cout<<temp[i]<<"\t\t路径长度为"<<d[index];
}
}
cout<<endl;
}
int initpath(int n){
for(int i=0;i<n;i++){
path[i]=i;
}
}
void InitG(){
for(int i=0;i<maxv;i++){
for(int j=0;j<maxv;j++){
G[i][j]=INF;
}
}
}
/*m为目标节点*/
void Dijkstra(int s,int n){
initpath(n);
//path[s]=s;//并查集初始化
fill(d,d+maxv,INF);
d[s]=0;
for(int i=0;i<n;i++){
int u=-1,Min=INF;
for(int j=0;j<n;j++){
if(vis[j]==false&&d[j]<Min){
u=j;
Min=d[j];
}
}
if(u==-1){
return ;
}
vis[u]=true;
for(int v=0;v<n;v++){
if(vis[v]==false&&G[u][v]!=INF&&G[u][v]+d[u]<d[v]){
d[v]=G[u][v]+d[u];
path[v]=u;
}
}
}
}
int main()
{
cout<<"请输入顶点数和边数："<<endl;
cin>>n>>m>>s;
int u,v,weight;
InitG();/*初始化全部为INF*/
for(int i=0;i<m;i++){
cin>>u>>v>>weight;
if(weight<G[u][v]){
/*防止这个两个顶点之间存在多条边*/
G[u][v]=weight;
}
}
Dijkstra(s,n);
for(int i=0;i<n;i++){
findfater(i);
}
return 0;
}
/*6个顶点 8条边 以0号节点为例子
6 8 1
0 1 1
0 3 4
0 4 4
1 3 2
2 5 1
3 2 2
3 4 3
4 5 3
0 1 5 3 4 6
*/
Prim algorithm
#include <bits/stdc++.h>
#define maxv 1000
#define INF 99999
using namespace std;
int G[maxv][maxv];
int d[maxv];/*d[i]代表着第i个节点到结合S的距离*/
bool vis[maxv]={
false};
void InitG(){
for(int i=0;i<maxv;i++){
for(int j=0;j<maxv;j++){
G[i][j]=INF;
}
}
}
int prim(int n){
int ans=0;
fill(d,d+maxv,INF);
d[0]=0;
for(int i=0;i<n;i++){
/*最外层循环是遍历每一个顶点*/
int u=-1,Min=INF;
for(int j=0;j<n;j++){
if(vis[j]==false&&d[j]<Min){
u=j;
Min=d[j];
}
}
if(u==-1){
return -1;
}
vis[u]=true;
ans+=d[u];
for(int v=0;v<n;v++){
if(vis[v]==false&&G[u][v]!=INF&&G[u][v]<d[v]){
d[v]=G[u][v];
}
}
}
return ans;
}
int main()
{
int n,m;
cout<<"请输入顶点数和边数："<<endl;
cin>>n>>m;
int u,v,weight;
InitG();/*初始化全部为INF*/
for(int i=0;i<m;i++){
cin>>u>>v>>weight;
if(weight<G[u][v]){
G[v][u]=G[u][v]=weight;
}
}
cout<<prim(n);
return 0;
}
/*
6 10
0 1 4
0 4 1
0 5 2
1 2 6
1 5 3
2 3 6
2 5 5
3 4 4
3 5 5
4 5 3
结果为15
*/