并查集算法

int find(int x)
{
    if(p[x] != x) p[x] = find(p[x]);
    return p[x];
}

#include

using namespace std;

const int N = 50005;
int n,K,fake;
int p[N],d[N];

int find(int x)
{
    if(p[x] != x)
    {
        int u = find(p[x]);
        d[x] += d[p[x]];
        p[x] = u;
    }
    return p[x];
}

int main()
{
    cin>>n>>K;
    for(int i = 1; i <= n; i ++ ) p[i] = i;
    while(K--)
    {
        int t,x,y;
        cin>>t>>x>>y;
        if(x > n || y > n) fake++;
        else
        {
            int px = find(x),py = find(y);
            if(t == 1)
            {
                if(px == py && (d[y] - d[x]) % 3) fake++;
                if(px != py)
                {
                    p[px] = py;
                    d[px] = d[y] - d[x];
                }
            }
            if(t == 2)
            {
                if(px == py && (d[x] - d[y] - 1) % 3) fake++;
                if(px != py)
                {
                    p[px] = py;
                    d[px] = d[y] - d[x] + 1;
                }
            }
        }
    }
    cout<