Kruskal algorithm to find the minimum spanning tree

Just write a template, the specific explanation will not speak, is a and check the application of the Set + greedy ideas.

Path compression is very useful, there is no compression when the tml three, after the compression of a lot faster, although still so slow

First of all, my compression method is to learn a bit and check the set:

1 intFind (intx)2 {3     intR=x;4      while(fa[r]!=r) r=Fa[r];5      while(x!=R) {6x=Fa[x];7fa[x]=R;8     }9     returnFa[x];Ten}

Non-recursive path compression, first find the Ancestor node, and then update the path from beginning to end each point, so that they directly point to the ancestor node

There is a recursive compression, code is not very understand, you can go to Baidu to learn a bit;

Then is the minimum spanning tree code, with a structure to save each pass the value and two nodes, the order from small to large, and then determine whether two points in a set, if the operation, if not on the operation, execution N-1 completed a minimum spanning tree

Rokua template Problem 3366:http://www.luogu.org/problem/show?pid=3366#sub

1#include <iostream>2#include <cstdio>3#include <algorithm>4#include <string>5 using namespacestd;6 #defineMAX 2000057 structnode{8     intLast , Next, Val;9 }node[max];Ten  One inteax5005],m,n,ans=0; A  - intFind (intx) - { the     intR=x; -      while(fa[r]!=r) r=Fa[r]; -      while(x!=R) { -x=Fa[x]; +fa[x]=R; -     } +     returnFa[x]; A } at  - voidWork () - { -     ints=0; -      for(intI=1; i<=m;i++){ -         if(s==m-1) Break; in         intFaa=Find (node[i].last); -         intfbb=Find (node[i].next); to         if(FAA! =FBB) { +fa[faa]=fbb; -ans+=Node[i].val; thes++; *         } $     }Panax Notoginseng } -  the BOOLCMP (node A, node B) + { A     returna.val<B.val; the } +  - voidInit () $ { $     inti; -Cin>>n>>M; -      for(i=1; i<=m;i++){ theCin>>node[i].last>>node[i].next>>Node[i].val; -     }WuyiSort (node+1, node+1+M, CMP); the      for(i=1; i<=n;i++){ -fa[i]=i; Wu     } - } About  $ intMain () - { - init (); - Work (); Acout<<ans; +     return 0; the}

Kruskal algorithm to find the minimum spanning tree