HDU 1232 Smooth Engineering introduction and check set with Daniel explanation

<span style= "font-family:arial, Helvetica, Sans-serif;" > #include <iostream></span> 

#include <cstring>
using namespace std;
int pre[1005];
int find (int x)
{
	int r=x;
	while (R!=pre[r])   //Search root node, (Pre[r] is the superior of R,) 
	R=pre[r];
	int i=x,j;
	while (I!=R)        //compression path, so that each child node superior directly to the root node, eliminating the layer of backtracking 
	{ 
	    j=pre[i];
		Pre[i]=r;
		i=j;
	}
	return r;
}

void Mix (int a,int b)
{ 
	int fx=find (a);   Select the root node
	int fy=find (b);   Select the root node 
	if (fx!=fy)        //If equal, that is the same root node, otherwise, with the node to merge  
	{
		pre[fx]=fy;   Root node Merge  
	}
} 

int main ()
{
	int n,m;
	while (Cin>>n>>m&&n)
	{
		
		bool t[1005];          Used to make the final statistic 
		int ans=-1;
		memset (t,0,sizeof (t));
		
		for (int i=1;i<=n;++i)
		pre[i]=i;              Initialize 
		
		int A, b;
		for (int i=1;i<=m;++i)
		{
			cin>>a>>b;
			Mix (A, b);          Merge Operation 
		} for
		
		(int i=1;i<=n;++i)
		    t[(Find (i))]=1;	  
		    
		for (int i=1;i<=n;++i)
		    if (T[i])
			ans++; 
			
		cout<<ans<<endl;
	}

Explanation: http://blog.csdn.net/kirito_j/article/details/51778229