bellmanford algorithm

最新推荐文章于 2024-07-10 23:54:17 发布

原创最新推荐文章于 2024-07-10 23:54:17 发布 · 293 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#algorithm #graph #struct #go #null #include

本文介绍了一个基于C++实现的图遍历算法，包括深度优先搜索（DFS）及其应用。通过具体代码展示了如何构建图结构，并利用DFS进行环检测与强连通分量的寻找。

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>

using namespace std;

typedef struct archnode{
  int to;
  int cost;
  struct archnode * next;
}archnode;
typedef struct vnode {
  int key;
  int cost;
  struct archnode *head;
}vnode;

typedef struct graph{
  int nodenum;
  int archnum;
  vnode ** root;
}graph;
void DF(vnode ** root,vnode *start,int color[]){
vnode *begin=start;
archnode * arch=begin->head;

cout<<"key is:"<<begin->key<<" "<<"value is:"<<begin->cost<<endl;
color[begin->key]=1;
while(arch!=NULL){
          cout<<"hhah"<<endl;
          archnode * next=arch->next;
          if(color[arch->to]==1)
          {
            cout<<"has loop"<<endl;
         return;
                         }
          if(color[arch->to]==0){
               DF(root,root[arch->to],color);
                  }
                  arch=next;
         }
         return;
}
void DF2(vnode ** root,vnode * start,int color[],int go[],int finish[],int time){
if(color[start->key]!=0)
return;
cout<<"time is"<<endl;
vnode *begin=start;
   archnode * arch=begin->head;
       cout<<"key is:"<<begin->key<<" "<<"value is:"<<begin->cost<<endl;
       color[begin->key]=1;
       go[begin->key]=time++;
       while(arch!=NULL){
          cout<<"haha"<<endl;
       archnode * next=arch->next;
       if(color[arch->to]==2){
         if(go[begin->key] > finish[arch->to])
         {
                  cout<<"not strongly connected componet"<<endl;
                  return;
         }

                }
                if(color[arch->to]==0)
                   DF2(root,root[arch->to],color,go,finish,time);
       arch=next;
         }
         color[begin->key]=2;
         finish[begin->key]=time++;
}
int main(){
int nodenum,archnum;
scanf("%d %d",&nodenum,&archnum);
graph * G=(graph*) malloc(sizeof(graph));
G->nodenum=nodenum;
G->archnum=archnum;
G->root =(vnode **)malloc(sizeof(vnode *)*(nodenum+1));
vnode ** root=G->root;
for(int index=0;index<nodenum;index++){
   root[index+1]=(vnode*)malloc(sizeof(vnode));
   root[index+1]->key=index+1;
   root[index+1]->cost=INT_MAX;
   root[index+1]->head=NULL;
}

for(int index=1;index<=archnum;index++){
   int from,to,cost;
   scanf("%d %d %d",&from,&to,&cost);
   //1
   vnode *nodeone=root[from];
   archnode *t1=nodeone->head;
   archnode * newone=(archnode *)malloc(sizeof(archnode));
   newone->to=to;
   newone->cost=cost;
   newone->next=NULL;
   nodeone->head=newone;
   newone->next=t1;
   //2
  // vnode * nodetwo=root[to];
  // archnode *t2=nodetwo->head;
  // archnode * newtwo=(archnode*)malloc(sizeof(archnode));
  // newtwo->to=from;
  // newtwo->cost=cost;
  // newtwo->next=NULL;
  // nodetwo->head=newtwo;
  // newtwo->next=t2;

   cout<<"index"<<endl;
}
int color[nodenum+1];
int go[nodenum+1];
int finish[nodenum+1];
for(int index=1;index<=nodenum;index++){
   color[index]=0;
  // go[index]=0;
  // finish[index]=0;
}
DF(G->root,root[1],color);
cout<<"test2"<<endl;
int time=1;
for(int index=1;index<=nodenum;index++){
   color[index]=0;
   go[index]=0;
   finish[index]=0;
}
for(int index=1;index<=nodenum;index++){
   cout<<"index "<<index<<endl;
     DF2(G->root,root[index],color,go,finish,time);
}

for(int index=1;index<=nodenum;index++){
   vnode * node=root[index];
   archnode * arch=node->head;
   while(arch!=NULL){
         archnode * next=arch->next;
         free(arch);
         arch=next;
         }
         free(root[index]);
         cout<<"delete"<<endl;
}
system("pause");
return 0;
}