python/TangDou/LuoGuBook/P2024.cpp

#include<bits/stdc++.h>

using namespace std;
const int N = 150010;
int fa[N];
int ans;
//带扩展域的并查集
/**
 * 功能：寻找祖先
 * @param x
 * @return
 */
int find(int x) {
    if (fa[x] != x) fa[x] = find(fa[x]);
    return fa[x];
}

//加入家族集合中
void join(int x, int y) {
    int f1 = find(x), f2 = find(y);
    if (f1 != f2)fa[f1] = f2;
}

int main() {
    int n, m;
    cin >> n >> m;
    //开三个并查集，合用一个数组表示
    //对于每种生物：设x为本身，x+n为猎物，x+2*n为天敌
    for (int i = 1; i <= 3 * n; i++) fa[i] = i; //初始化

    while (m--) {
        int x, y, t;
        cin >> t >> x >> y;
        // 太大了，越界了，肯定是假话
        if (x > n || y > n) {
            ans++;
            continue;
        }
        //xy同类
        if (t == 1) {
            //如果y是x的天敌或猎物，为谎言
            if (find(x + n) == find(y) || find(x + 2 * n) == find(y)) {
                ans++;
                continue;
            }
            //x的同类和y的同类，x的猎物是y的猎物，x的天敌是y的天敌
            join(x, y);
            join(x + n, y + n);
            join(x + 2 * n, y + 2 * n);
        }
        //y是x的猎物
        if (t == 2) {
            //如果x是y的同类或猎物，为谎言
            if (find(x) == find(y) || find(x + 2 * n) == find(y)) {
                ans++;
                continue;
            }
            join(x, y + 2 * n);//x的同类是y的天敌
            join(x + n, y);//x的猎物是y的同类
            join(x + 2 * n, y + n); //x的天敌是y的猎物
        }
    }
    printf("%d\n", ans);
    return 0;
}