并查集

/*并查集*/
#include<stdio.h>

int *a;
int *sz;
int count;  //the number of connected component

//union two connected components with weights
void union_two_points(int p, int q)
{
  int i = root(p);
  int j = root(q);
  if(i == j) return;
  if(sz[i] < sz[j]) 
  {
     a[i] = j;
     sz[j] += sz[i];
  }
  else
  {
     a[j] = i;
     sz[i] += sz[j];
  }
  count--;
}


//test if p and q are connected
int connected(int p, int q)
{
  return root[p] == root[q];
}


//find the root point
int root(int p)
{
   while(p != a[p])
   {
      p = a[p];
   }
   return p;
}


int main()
{
   int T;
   printf("Please input the number of points：");
   scanf("%d",&T);

   count = T;
   a = (int*)malloc(sizeof(int)*T);
   sz = (int*)malloc(sizeof(int)*T);

   memset(sz,1,T*sizeof(int));      //set the size array
   //initial the array 
   for(int i=0;i<T;i++)
   {
      a[i] = i;
   }

   /*
   operation
   */
}