51nod2004 终结之时 (支配树+树剖+树链的并)

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我永远喜欢洛天依

给定一张图世末积雨云，你需要维护其支配树：

单点修改，子树修改，树链修改

子树求和，树链求和，多条树链的并集求和

撤销之前的操作

可以先用 Lengauer-Tarjan 算法 求出图的支配树，然后把它树剖，开一个线段树维护

至于多条树链的并集求和（有点像虚树的那种操作），现将所有点按照 dfn 排序，然后按照 dfn 的顺序依次加点

枚举节点a[i]，每次假装a[1..i]的答案中除了a[i]到根的路径没有求值之外其它的都求值了，那么转移的时候需要加上当前点到lca的距离。

如图，我们从1转移到2时候，要加上绿色的链这一段的值

最后转移完后，我们再加上最后一个点到根的距离即可

至于撤销操作，我们可以考虑建立主席树，当然也可以不建主席树暴力撤销，因为每一步操作最多只会被撤销一次。

代码：

#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;

int n, m;

namespace dominate_tree
{
	vector<int> g[50010], g1[50010], g2[50010];
	int sdom[50010], bel[50010], val[50010], idom[50010];
	int dfn[50010], dfntot, id[50010], fa[50010];

	void dfs(int x)
	{
		dfn[x] = ++dfntot, id[dfntot] = x;
		for (int i : g[x]) if (dfn[i] == 0) fa[i] = x, dfs(i);
	}

	int getf(int x)
	{
		if (x == bel[x]) return x;
		int rt = getf(bel[x]);
		if (dfn[sdom[val[bel[x]]]] < dfn[sdom[val[x]]])
			val[x] = val[bel[x]];
		return bel[x] = rt;
	}
	
	void work()
	{
		for (int i = 1; i <= n; i++) sdom[i] = bel[i] = val[i] = i;
		dfs(1);
		for (int i = n; i >= 2; i--)
		{
			int x = id[i];
			for (int j : g1[x])
				if (dfn[j])
				{
					getf(j);
					if (dfn[sdom[val[j]]] < dfn[sdom[x]])
						sdom[x] = sdom[val[j]];
				}
			g2[sdom[x]].push_back(x);
			x = bel[x] = fa[x];
			for (int j : g2[x])
			{
				getf(j);
				if (sdom[val[j]] == x) idom[j] = x;
				else idom[j] = val[j];
			}
		}
		for (int i = 2; i <= n; i++)
		{
			int x = id[i];
			if (idom[x] != sdom[x]) idom[x] = idom[idom[x]];
		}
	}
}

vector<int> out[50010];
int fa[50010], depth[50010], wson[50010], weight[50010];
int dfn[50010], top[50010], tot, val[50010], stop, tmp[50010];
long long tree[200010], lazy[200010];
struct ch { int type, u, w; } s[100010];

void pushdown(int x, int cl, int mid, int cr)
{
	lazy[x * 2] += lazy[x], lazy[x * 2 + 1] += lazy[x];
	tree[x * 2] += lazy[x] * (mid - cl + 1);
	tree[x * 2 + 1] += lazy[x] * (cr - mid);
	lazy[x] = 0;
}

void chenge(int x, int cl, int cr, int L, int R, int k)
{
	if (cr < L || R < cl) return;
	if (L <= cl && cr <= R) { lazy[x] += k, tree[x] += (cr - cl + 1) * (long long)k; return; }
	int mid = (cl + cr) / 2;
	pushdown(x, cl, mid, cr);
	chenge(x * 2, cl, mid, L, R, k), chenge(x * 2 + 1, mid + 1, cr, L, R, k);
	tree[x] = tree[x * 2] + tree[x * 2 + 1];
}

long long query(int x, int cl, int cr, int L, int R)
{
	if (cr < L || R < cl) return 0;
	if (L <= cl && cr <= R) return tree[x];
	int mid = (cl + cr) / 2;
	pushdown(x, cl, mid, cr);
	return query(x * 2, cl, mid, L, R) + query(x * 2 + 1, mid + 1, cr, L, R);
}

void dfs1(int x)
{
	wson[x] = -1, weight[x] = 1;
	for (int i : out[x])
	{
		fa[i] = x, depth[i] = depth[x] + 1, dfs1(i), weight[x] += weight[i];
		if (wson[x] == -1 || weight[i] > weight[wson[x]]) wson[x] = i;
	}
}

void dfs2(int x, int topf)
{
	dfn[x] = ++tot, top[x] = topf;
	if (wson[x] != -1)
	{
		dfs2(wson[x], topf);
		for (int i : out[x]) if (i != wson[x]) dfs2(i, i);
	}
}

int lca(int x, int y)
{
	while (top[x] != top[y])
	{
		if (depth[top[x]] < depth[top[y]]) swap(x, y);
		x = fa[top[x]];
	}
	if (depth[x] > depth[y]) swap(x, y);
	return x;
}

long long getans(int x)
{
	long long res = 0;
	while (x)
		res += query(1, 1, n, dfn[top[x]], dfn[x]), x = fa[top[x]];
	return res;
}

int main()
{
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++) scanf("%d", &val[i]);
	for (int x, y, i = 1; i <= m; i++)
		scanf("%d%d", &x, &y), dominate_tree::g[x].push_back(y), dominate_tree::g1[y].push_back(x);
	dominate_tree::work();
	for (int i = 2; i <= n; i++) out[dominate_tree::idom[i]].push_back(i);
	dfs1(1), dfs2(1, 1);
	for (int i = 1; i <= n; i++) chenge(1, 1, n, dfn[i], dfn[i], val[i]);
	int q; scanf("%d", &q);
	for (int i = 1; i <= q; i++)
	{
		char tp;
		scanf(" %c", &tp);
		if (tp == 'C')
		{
			int opd, u, w;
			scanf("%d%d%d", &opd, &u, &w);
			s[++stop] = (ch){opd, u, w};
			if (opd == 1) chenge(1, 1, n, dfn[u], dfn[u], w);
			if (opd == 2) chenge(1, 1, n, dfn[u], dfn[u] + weight[u] - 1, w);
			if (opd == 3)
				while (u) chenge(1, 1, n, dfn[top[u]], dfn[u], w), u = fa[top[u]];
		}
		else if (tp == 'Q')
		{
			int opd, u;
			scanf("%d%d", &opd, &u);
			if (opd == 1) printf("%lld
", query(1, 1, n, dfn[u], dfn[u] + weight[u] - 1));
			if (opd == 2) printf("%lld
", getans(u));
			if (opd == 3)
			{
				long long res = 0;
				for (int j = 1; j <= u; j++) scanf("%d", &tmp[j]);
				sort(tmp + 1, tmp + 1 + u, [](int x, int y) { return dfn[x] < dfn[y]; });
				for (int j = 2; j <= u; j++)
				{
					int lc = lca(tmp[j - 1], tmp[j]);
					if (lc != tmp[j - 1])
						res += getans(tmp[j - 1]) - getans(lc);
				}
				res += getans(tmp[u]);
				printf("%lld
", res);
			}
		}
		else
		{
			int k;
			scanf("%d", &k);
			while (stop > 0 && k > 0)
			{
				int opd = s[stop].type, u = s[stop].u, w = -s[stop].w;
				if (opd == 1) chenge(1, 1, n, dfn[u], dfn[u], w);
				if (opd == 2) chenge(1, 1, n, dfn[u], dfn[u] + weight[u] - 1, w);
				if (opd == 3)
					while (u) chenge(1, 1, n, dfn[top[u]], dfn[u], w), u = fa[top[u]];
				stop--, k--;
			}
		}
	}
	return 0;
}