并查集

int par[maxn];//父节点
int deep[maxn];深度

void init(int n) {
    for (int i = 0; i < 0; i++) {
        par[i] = i;
        deep[i] = 0;
    }
}

int find(int x) {
    if (par[x] == x) {
        return x;
    }
    else {
        return par[x] = find(par[x]);
    }
}

void unite(int x, int y) {
    x = find(x);
    y = find(y);
    if (x == y) return;
    if (deep[x] < deep[y]) {
        par[x] = y;
    }
    else {
        par[y] = x;
        if (deep[x] == deep[y]) deep[x]++;
    }
}

bool same(int x,int y) {
    return find(x) == find(x);
}