2023-8-25食物链

题目链接：食物链

#include <iostream>using namespace std;const int N = 50010;int n, m;
int p[N], d[N];int find(int x)
{if(p[x] != x){int t = find(p[x]);d[x] += d[p[x]];p[x] = t;}return p[x];
}int main()
{cin >> n >> m;for(int i = 1; i <= n; i++) p[i] = i;int res = 0;while(m --){int t, x ,y;cin >> t >> x >> y;int px = find(x), py = find(y);if(x > n || y > n) res ++;else{if(t == 1){if(px == py && (d[x] - d[y]) % 3) res++;else if(px != py){p[px] = py;d[px] = d[y] - d[x];}}else{if(px == py && (d[x] - 1 - d[y]) % 3) res ++;else if(px != py){p[px] = py;d[px] = d[y] - d[x] + 1;}}}}cout << res << endl;
}