并查集C++实现

#include <iostream>

using namespace std;
class UF    {
//cnt is the number of disjoint sets.
//id is an array that records distinct identity of each set,when two sets are merged ,their id will be same.
//sz is an array that records the child number of each set including the set self.
int *id, cnt, *sz;
public:
// Create an empty union find data structure with N isolated sets.
UF(int N)   {
cnt = N;
id = new int
;
sz = new int
;
for (int i = 0; i<N; i++)	{
id[i] = i;
sz[i] = 1;
}
}
~UF()	{
delete[] id;
delete[] sz;
}
// Return the id of component corresponding to object p.
int find(int p)	{

if (p != id[p]){
id[p] = find(id[p]);
}
return id[p];
}
// Replace sets containing x and y with their union.
void merge(int x, int y)	{
int i = find(x);
int j = find(y);
if (i == j) return;

// make smaller root point to larger one
if (sz[i] < sz[j])	{
id[i] = j;
sz[j] += sz[i];
}
else	{
id[j] = i;
sz[i] += sz[j];
}
cnt--;
}
// Are objects x and y in the same set?
bool connected(int x, int y)    {
return find(x) == find(y);
}
// Return the number of disjoint sets.
int count() {
return cnt;
}
};

void main(){
UF test(5);
test.merge(2, 3);
test.merge(3, 4);
cout << test.find(4);
cout << test.count();
}