B-networking POJ-1287

Main topic:

To find the minimum spanning tree. Enter a n,k. n indicates that there are n points, followed by k lines, each line entered three digits a,b,c, meaning: the distance between AB is C. End input when n=0.

n<=50,k<=100

Problem Solving Ideas:

Set of templates. Note There may be duplicate paths. such as 1 2 6, 2 1 8. 1 2 6 will be taken at this time.

1#include <iostream>2#include <vector>3#include <map>4#include <string>5#include <queue>6#include <stack>7#include <algorithm>8#include <Set>9 Ten#include <cstdio> One#include <cstring> A#include <cmath> -#include <cstdlib> - using namespacestd; the  - Const intinf=0x3f3f3f3f; - Const intSize= -;///I don't know how big it is to drive a bigger one. -  + intId[size]; - intSz[size]; + intM,n; A  at structnode{ -     intstart; -     intend; -     intVal; -  -}edge[10000];///emmmm in voidClear () - { to      for(intI=0; i<=n;i++) +     { -id[i]=i;sz[i]=1; the     } * } $ intFindintx)Panax Notoginseng { -     if(X!=id[x]) id[x]=find (Id[x]); the     returnId[x]; + } A  the voidUnintPintq) + { -p=find (p); $q=find (q); $     if(P==Q)return ; -     if(sz[p]<Sz[q]) -id[p]=find (q); the     Else -     {Wuyi         if(sz[p]==Sz[q]) thesz[p]++; -id[q]=find (p); Wu     } - } About  $ intKruskal () - { -     intsum=0; -      for(intI=0; i<m;i++) A     { +         if(Find (edge[i].start)! =find (edge[i].end)) the         { - un (edge[i].start,edge[i].end); $sum+=Edge[i].val; the         } the     } the     returnsum; the  - } in  the BOOLCMP (node A,node b) the { About     returna.val<B.val; the } the intMain () the { +      while(cin>>N) -     { the         if(n==0) Break;BayiCin>>m; the Clear (); the         intA,b,value; -          for(intI=0; i<m;i++) -         { theCin>>a>>b>>value; theedge[i].start=A; theEdge[i].end=b; theEdge[i].val=value; -         } theSort (edge,edge+m,cmp); theCout<<kruskal () <<Endl; the     }94     return 0; the}

Kruskal Algorithm

1#include <iostream>2#include <vector>3#include <map>4#include <string>5#include <queue>6#include <stack>7#include <Set>8 9#include <cstdio>Ten#include <cstring> One#include <cmath> A#include <cstdlib> - using namespacestd; -  the Const intinf=0x3f3f3f3f; - Const intSize= -; -  - intDis[size]; + intGraph[size][size]; - intn,m; + intVis[size]; A  at intPrim () - { -memset (Vis,0,sizeof(Vis)); -     intindex; -     intsum=0; -      for(intI=1; i<=n;i++)///starting point is 1 indis[i]=graph[i][1]; -vis[1]=1; to      for(intI=2; i<=n;i++) +     { -         intminn=INF; the          for(intj=1; j<=n;j++) *             if(!vis[j]&&dis[j]<Minn) $         {Panax Notoginsengminn=dis[j];index=J; -         } thevis[index]=1; +sum+=Minn; A          for(intj=1; j<=n;j++) the             if(dis[j]>graph[j][index]&&!Vis[j]) +dis[j]=Graph[j][index]; -     } $     returnsum; $ } - intMain () - { the       while(cin>>N) -     {Wuyi         if(n==0) Break; theCin>>m; -memset (Graph,inf,sizeof(graph)); Wu         intA,b,value; -          for(intI=0; i<m;i++) About         { $Cin>>a>>b>>value; -             if(Graph[a][b]>value)///just keep repeating. -graph[a][b]=graph[b][a]=value; -         } ACout<<prim () <<Endl; +     } the     return 0; -}

Prim Algorithm

B-networking POJ-1287