loj 2955 「NOIP2018」保卫王国 - 树链剖分 - 动态规划

题目传送门

　　传送门

　　想抄一个短一点ddp板子。然后照着Jode抄，莫名其妙多了90行和1.3k。

Code

/**
 * loj
 * Problem#2955
 * Accepted
 * Time: 2653ms
 * Memory: 25616k
 */
#include 
using namespace std;
typedef bool boolean;

const int N = 1e5 + 5;

#define ll long long

template 
T smin(T a, T b) {
	return min(a, b);
}
template 
T smin(T a, const Q &...args) {
	return min(a, smin(args...));
}

const ll llf = 1e12;

typedef class Data {
	public:
		ll a[2][2];

		Data() {	}
		Data(ll x) {
			a[0][0] = llf, a[0][1] = 0;
			a[1][0] = x, a[1][1] = x;
		}
		Data(ll x, ll y, ll z, ll w) {
			a[0][0] = x, a[0][1] = y;
			a[1][0] = z, a[1][1] = w;
		}

		Data get() {
			ll g = min(a[0][0], a[0][1]);
			ll f = min(a[1][0], a[1][1]);
			g = min(g, f);
			return Data(f, f, g, g);
		}
		ll* operator [] (int p) {
			return a[p];
		}
		friend Data operator * (Data a, Data b) {
			Data rt;
			rt[0][0] = min(a[0][0] + b[0][0], a[0][1] + b[1][0]);
			rt[0][1] = min(a[0][0] + b[0][1], a[0][1] + b[1][1]);
			rt[1][0] = min(a[1][0] + b[0][0], a[1][1] + b[1][0]);
			rt[1][1] = min(a[1][0] + b[0][1], a[1][1] + b[1][1]);
			return rt;
		}
		friend Data operator + (Data a, Data b) {
			Data rt;
			rt[0][0] = a[0][0] + b[0][0];
			rt[0][1] = a[0][1] + b[0][1];
			rt[1][0] = a[1][0] + b[1][0];
			rt[1][1] = a[1][1] + b[1][1];
			return rt;
		}
		friend Data operator - (Data a, Data b) {
			Data rt;
			rt[0][0] = a[0][0] - b[0][0];
			rt[0][1] = a[0][1] - b[0][1];
			rt[1][0] = a[1][0] - b[1][0];
			rt[1][1] = a[1][1] - b[1][1];
			return rt;
		}
		ll get_ans() {
			ll rt = smin(a[0][0], a[0][1], a[1][0], a[1][1]);
			return (rt >= llf) ? (-1) : (rt);
		}
} Data;

typedef class SegTreeNode {
	public:
		Data d;
		SegTreeNode *fa;
		SegTreeNode *l, *r;

		void push_up() {
			d = l->d * r->d;
		}
} SegTreeNode;

typedef class Chain {
	public:
		SegTreeNode *st;
		int len, top;

		Chain() {	}
		Chain(int top);

		void update(int, Data, Data);
} Chain;

SegTreeNode pool[N << 1];
SegTreeNode *_top = pool;

int S[N];
Data dat[N];

int tp;
Chain *ch[N];
SegTreeNode *tr[N];

void build(SegTreeNode*& p, int l, int r) {
	p = _top++;
	if (l == r) {
		p->d = dat[S[l]];
		tr[S[l]] = p;
		return;
	}
	int mid = (l + r) >> 1;
	build(p->l, l, mid);
	build(p->r, mid + 1, r);
	p->push_up();
	p->l->fa = p;
	p->r->fa = p;
}

Chain::Chain(int top) : st(_top), len(tp), top(top) {
	reverse(S + 1, S + tp + 1);
	build(st, 1, len);
	for (int i = 1; i <= len; i++) {
		ch[S[i]] = this;
	} 
	if (top) {
		dat[top] = dat[top] + st->d.get();
	}
}

void Chain::update(int x, Data old_d, Data new_d) {
	Data nold_d = st->d.get();
	tr[x]->d = tr[x]->d - old_d + new_d;
	for (SegTreeNode *p = tr[x]->fa; p; p = p->fa)
		p->push_up();
	if (top) {
		ch[top]->update(top, nold_d, st->d.get());
	}
}

int n, m;
int p[N];
int sz[N], zson[N];
vector G[N];

void dfs1(int p, int fa) {
	int mx = 0, &id = zson[p];
	sz[p] = 1;
	for (auto e : G[p]) {
		if (e ^ fa) {
			dfs1(e, p);
			sz[p] += sz[e];
			if (mx < sz[e]) {
				mx = sz[e];
				id = e;
			}
		}
	}
}

void dfs2(int p, int fa) {
	if (zson[p]) {
		for (auto e : G[p]) {
			if ((e ^ fa) && (e ^ zson[p])) {
				dfs2(e, p);
				new Chain(p);
			}
		}
		dfs2(zson[p], p);
	} else {
		tp = 0;
	}
	S[++tp] = p;
}

int main() {
	freopen("defense.in", "r", stdin);
	freopen("defense.out", "w", stdout);
	scanf("%d%d%*s", &n, &m);
	for (int i = 1, x; i <= n; i++) {
		scanf("%d", &x);
		dat[i] = x;
		p[i] = x;
	}
	for (int i = 1, u, v; i < n; i++) {
		scanf("%d%d", &u, &v);
		G[u].push_back(v);
		G[v].push_back(u);
	}
	dfs1(1, 0);
	dfs2(1, 0);
	new Chain(0);
	int a, x, b, y;
	while (m--) {
		scanf("%d%d%d%d", &a, &x, &b, &y);
		Data olda = p[a], oldb = p[b];
		Data na = Data(llf * (1 - x)), nb = Data(llf * (1 - y));
		ch[a]->update(a, olda, na);
		ch[b]->update(b, oldb, nb);
		ll ans = ch[1]->st->d.get_ans() + olda[1][0] * x + oldb[1][0] * y;
		ch[a]->update(a, na, olda);
		ch[b]->update(b, nb, oldb);
		printf("%lld\n", ans);
	}
	return 0;
}