种类并查集——洛谷P2024食物链

#include<bits/stdc++.h>
using namespace std;
#define maxn 1500100
int f[maxn];
int find(int x)
{
    
    
	if(x == f[x])return x;
	else return f[x] = find(f[x]);
}
int merge(int x,int y)
{
    
    
	int p = find(x),q = find(y);
	f[p] = q;
}
int check(int x,int y)
{
    
    
	if(find(x)!=find(y))return 0;
	else return 1;
}
int main()
{
    
    
	int n,k;
	scanf("%d%d",&n,&k);
	for(int i=1;i<=n*3;i++)f[i] = i;
	int ans = 0;
	for(int i=1;i<=k;i++)
	{
    
    
		int q,u,v;
		scanf("%d%d%d",&q,&u,&v);
		if(u>n||v>n){
    
    
			ans++;
			continue;
		}
		if(q==1){
    
    
			if(check(u,v+n)||check(u,v+n*2))
			{
    
    
				ans++;
				continue;
			}else
			{
    
    
				merge(u,v);
				merge(u+n,v+n);
				merge(u+n*2,v+n*2);
			}
		}
		if(q==2)
		{
    
    
			if(check(u,v)||check(u,v+2*n))
			{
    
    
				ans++;
				continue;
			}
			else{
    
    
				merge(u,v+n);
				merge(u+n,v+2*n);
				merge(u+2*n,v);
			}
		}
	}
	cout<<ans<<endl;
}