Dijkstra

Dijkstra

 

 

 

1 #include <iostream>
  2 #include <cstring>
  3 using namespace std;
  4 
  5 const int INF=0x3fffffff;
  6 
  7 //最短路径
  8 struct closedge{
  9     int adjvex;
 10     int lowcost;
 11     bool visited;
 12 }closedge[105];
 13 int am[105][105];
 14 int n,m;
 15 int start,end;//started ended
 16 
 17 void printAm();
 18 void printLowCost();
 19 
 20 void init(){
 21     memset(am,127/3,sizeof(am));
 22     cin>>n>>m;
 23     int a,b,val;
 24     for(int i=1;i<=m;i++){
 25         cin>>a>>b>>val;
 26         am[a][b]=val;
 27     }
 28     cin>>start>>end;
 29 
 30     for(int i=1;i<=n;i++){
 31         closedge[i].adjvex=start;
 32         closedge[i].lowcost=am[start][i];
 33         closedge[i].visited=false;
 34     }
 35 }
 36 
 37 void dijkstra(){
 38     int k=n-1;
 39     while(k--){
 40         //找到最小
 41         printLowCost();
 42             int min=0x3fffffff,min_i=0;
 43             for(int i=1;i<=n;i++){
 44                 if(!closedge[i].visited&&closedge[i].lowcost<min){
 45                     min=closedge[i].lowcost;
 46                     min_i=i;
 47                 }
 48             }
 49             closedge[min_i].visited=true;
 50             //用这个最小的点去更新closedge
 51             for(int i=1;i<=n;i++){
 52                 if(!closedge[i].visited){
 53                     if(closedge[i].lowcost>am[min_i][i]+min){
 54                         closedge[i].lowcost=am[min_i][i]+min;
 55                         closedge[i].adjvex=min_i;
 56                     }
 57                 }
 58             }
 59     }
 60     cout<<closedge[end].lowcost<<endl;
 61 }
 62 
 63 void findWay(int end){
 64     if(end==start){
 65         cout<<start<<" ";
 66     }
 67     else{
 68         findWay(closedge[end].adjvex);
 69         cout<<end<<" ";
 70     }
 71 
 72 
 73 }
 74 
 75 int main() {
 76     freopen("src/in.txt","r",stdin);
 77     init();
 78     dijkstra();
 79     printAm();
 80     findWay(end);
 81 
 82     return 0;
 83 }
 84 
 85 void printLowCost(){
 86     for(int i=1;i<=n;i++){
 87         printf("%10d ",closedge[i].lowcost);
 88     }
 89     cout<<endl;
 90 }
 91 
 92 void printAm(){
 93     cout<<start<<" "<<end<<endl;
 94     for(int i=1;i<=n;i++){
 95         for(int j=1;j<=n;j++){
 96             printf("%10d ",am[i][j]);
 97         }
 98         cout<<endl;
 99     }
100 }