https://www.luogu.org/problemnew/show/P2024

题解：

https://www.luogu.org/blog/Sooke/solution-p2024

 

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=100000+10;
const int M=100000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,q;
int ans,cnt,flag,temp,sum,a,b,c;
int pre[N*3];
char str;
struct node{};
int find(int x){if(x==pre[x])return x;return pre[x]=find(pre[x]);}
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    //cout.tie(0);
    //scanf("%d",&t);
    //while(t--){
    scanf("%d%d",&n,&m);
    for(int i=1;i<=3*n;i++)pre[i]=i;
    for(int i=1;i<=m;i++){
        scanf("%d%d%d",&c,&a,&b);
        if(a<=n&&b<=n){
            if(c==1){
                if(find(a)==find(b+n)||find(b)==find(a+n))ans++;
                else{
                    pre[find(a)]=find(b);
                    pre[find(a+n)]=find(b+n);
                    pre[find(a+2*n)]=find(b+2*n);
                }
            }else{
                if(find(a)==find(b)||find(b+n)==find(a))ans++;
                else{
                    pre[find(a+n)]=find(b);
                    pre[find(a+2*n)]=find(b+n);
                    pre[find(a)]=find(b+2*n);
                }
            }
        }else{
            ans++;
        }
    }
    cout<<ans<<endl;
    //}

#ifdef DEBUG
	printf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC);
#endif
    //cout << "Hello world!" << endl;
    return 0;
}