BZOJ 3123: [Sdoi2013]森林

我以为有多组数据，原来第一个数是数据编号，绝了
只有连边操作，启发式合并即可。
然后就是主席树裸题了。
空间要开大一点，因为主席树我不知道怎么回收空间。。

#include <bits/stdc++.h>
#define l(p) tree[p].l
#define r(p) tree[p].r
#define mid ((l + r) >> 1)

namespace IO {
	inline void read() {}
	template<class T, class... T2>
	inline void read(T &x, T2 &... oth) {
		T f = 1; x = 0; char ch = getchar();
		while (!isdigit(ch)) { if (ch == '-') f = -1; ch = getchar(); }
		while (isdigit(ch)) x = x * 10 + ch - 48, ch = getchar(); 
		x *= f;
		read(oth...);
	}
}

const int N = 1e5 + 7, ALL = 1e9 + 7;
int head[N], cnt = 1, to[N * 2], ne[N * 2], Fa[N], fa[N][19];
int n, m, q, root[N], dep[N], version[N], val[N];
int sz[N];

inline void add(int u, int v) {
	to[++cnt] = v; ne[cnt] = head[u]; head[u] = cnt;
}

struct Seg {
	struct Tree {
		int l, r, sum;
	} tree[N * 200];
	int tol;
	void update(int &p, int q, int l, int r, int pos) {
		tree[p = ++tol] = tree[q];
		tree[p].sum++;
		if (l == r) return;
		if (pos <= mid) update(l(p), l(q), l, mid, pos);
		else update(r(p), r(q), mid + 1, r, pos);
	}
	int query(int p, int q, int lca, int fa_lca, int l, int r, int k) {
		if (l == r) return l;
		int sum = tree[l(p)].sum + tree[l(q)].sum - tree[l(lca)].sum - tree[l(fa_lca)].sum;
		if (sum >= k) return query(l(p), l(q), l(lca), l(fa_lca), l, mid, k);
		return query(r(p), r(q), r(lca), r(fa_lca), mid + 1, r, k - sum);
	}
} seg;

void dfs(int u, int f, int F) {
	sz[F]++; Fa[u] = F; fa[u][0] = f; dep[u] = dep[f] + 1;
	for (int i = 1; i <= 17; i++)
		fa[u][i] = fa[fa[u][i - 1]][i - 1];
	seg.update(root[u], root[f], 0, ALL, val[u]);
	for (int i = head[u]; i; i = ne[i]) {
		int v = to[i];
		if (Fa[v] == F || v == f) continue;
		dfs(v, u, F);
	}
}

int Lca(int u, int v) {
	if (dep[u] < dep[v]) std::swap(u, v);
	int dif = dep[u] - dep[v];
	for (int i = 17; ~i; i--) 
		if (dif >> i & 1)
			u = fa[u][i];
	if (u == v) return u;
	for (int i = 17; ~i; i--)
		if (fa[u][i] != fa[v][i])
			u = fa[u][i], v = fa[v][i];
	return fa[u][0];
}

void solve() {
	IO::read(n, m, q);
	for (int i = 1; i <= n; i++)
		IO::read(val[i]);
	for (int i = 1, u, v; i <= m; i++) {
		IO::read(u, v);
		add(u, v);
		add(v, u);
	}
	for (int i = 1; i <= n; i++)
		if (!Fa[i]) dfs(i, 0, i);
	int ans = 0;
	for (int x, y, k; q--; ) {
		char s[3];
		scanf("%s", s);
		IO::read(x, y);
		x ^= ans, y ^= ans;
		if (s[0] == 'Q') {
			IO::read(k);
			k ^= ans;
			int ll = Lca(x, y);
			printf("%d\n", ans = seg.query(root[x], root[y], root[ll], root[fa[ll][0]], 0, ALL, k));
		} else {
			if (sz[Fa[x]] < sz[Fa[y]]) std::swap(x, y);
			add(x, y); add(y, x);
			dfs(y, x, Fa[x]);
		}
	}
}

int main() {
	int T;
	IO::read(T);
	solve();
	return 0;
}