P2024 食物链

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
using namespace std;
int n, m, order, a, b, ans, fa[100005], re[100005];
int find(int x)
{
    int f = fa[x];
    if(x != f) {
        fa[x] = find(f);
        re[x] = (re[x] + re[f]) % 3;
        return fa[x];
    }
    else return f;
}
int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; i++)
        fa[i] = i;
    for(int i = 1; i <= m; i++) {
        cin >> order >> a >> b;
        if(a > n || b > n || (a == b && order == 2)) {
            ans++;
            continue;
        }
        int f1 = find(a), f2 = find(b);
        if(order == 1) {
            if(f1 == f2 && re[a] != re[b]) {
                ans++;
                continue;
            } /*else if(f1 == f2 && re[a] % 3 == re[b] % 3) {
                continue;
            }*/ else if(f1 != f2) {
                fa[f1] = f2;
                re[f1] = (re[b] - re[a] + 3) % 3;
                continue;
            }
        } else if(order == 2) {
            if(f1 == f2 && (re[a] - re[b] + 3) % 3 != 1) {
                ans++;
                continue;
            } else if(f1 != f2) {
                fa[f1] = f2;
                re[f1] = (re[b] + 1 - re[a] + 3) % 3;
                continue;
            }
        }
    }
    cout << ans;
return 0;
}