并查集(图论) LA 3644 X-Plosives

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;
struct DSU	{
int rt
, rk
;
void init(void)	{
memset (rt, -1, sizeof (rt));
memset (rk, 0, sizeof (rk));
}
int Find(int x)	{
return rt[x] == -1 ? x : rt[x] = Find (rt[x]);
}
void Union(int x, int y)	{
x = Find (x);	y = Find (y);
if (x == y)	return ;
if (rk[x] > rk[y])	{
rt[y] = x;	rk[x] += rk[y] + 1;
}
else	{
rt[x] = y;	rk[y] += rk[x] + 1;
}
}
bool same(int x, int y)	{
return Find (x) == Find (y);
}
}dsu;

int main(void)	{
dsu.init ();
int ans = 0, x, y;
while (scanf ("%d", &x) == 1)	{
if (x == -1)	{
printf ("%d\n", ans);
dsu.init ();	ans = 0;
continue;
}
scanf ("%d", &y);
if (dsu.same (x, y))	ans++;
else	dsu.Union (x, y);
}

return 0;
}