WC simulation (1.8) T3 send you a Christmas tree

give you a christmas tree

Topic background:

1.8 WC Simulation T3

Analysis: Union search  +  heap  +  greedy

 

For the point with the global minimum, after selecting its parent, it must be selected, so we directly merge it and its parent, then for a point set i , record ti as the number of points in the point set, and Si as The sum of the weights of the points in the point set, then, for two point sets, if the point set i is better than the point set j , then t _i  * s _j  > t _j  * s _i , then s _i  /t _i  < s _j  / t _j , then directly merge the set  +  heap, and merge the current block and the parent's block each time.

 

Source:

/*
	created by scarlyw
*/
#include <cstdio>
#include <string>
#include <algorithm>
#include <cstring>
#include <iostream>
#include <cmath>
#include <cctype>
#include <vector>
#include <set>
#include <queue>
#include <ctime>
#include <bitset>

inline char read() {
	static const int IN_LEN = 1024 * 1024;
	static char buf[IN_LEN], *s, *t;
	if (s == t) {
		t = (s = buf) + fread(buf, 1, IN_LEN, stdin);
		if (s == t) return -1;
	}
	return *s++;
}

///*
template<class T>
inline void R(T &x) {
	static char c;
	static bool iosig;
	for (c = read(), iosig = false; !isdigit(c); c = read()) {
		if (c == -1) return ;
		if (c == '-') iosig = true;	
	}
	for (x = 0; isdigit(c); c = read())
		x = ((x << 2) + x << 1) + (c ^ '0');
	if (iosig) x = -x;
}
//*/

const int OUT_LEN = 1024 * 1024;
char obuf[OUT_LEN], *oh = obuf;
inline void write_char(char c) {
	if (oh == obuf + OUT_LEN) fwrite(obuf, 1, OUT_LEN, stdout), oh = obuf;
	*oh++ = c;
}

template<class T>
inline void W(T x) {
	static int buf[30], cnt;
	if (x == 0) write_char('0');
	else {
		if (x < 0) write_char('-'), x = -x;
		for (cnt = 0; x; x /= 10) buf[++cnt] = x % 10 + 48;
		while (cnt) write_char(buf[cnt--]);
	}
}

inline void flush() {
	fwrite(obuf, 1, oh - obuf, stdout);
}

/*
template<class T>
inline void R(T &x) {
	static char c;
	static bool iosig;
	for (c = getchar(), iosig = false; !isdigit(c); c = getchar())
		if (c == '-') iosig = true;	
	for (x = 0; isdigit(c); c = getchar())
		x = ((x << 2) + x << 1) + (c ^ '0');
	if (iosig) x = -x;
}
//*/

const int MAXN = 30000 + 10;

struct node {
	int to, s, t;
	node(int to = 0, int s = 0, int t = 0) : to(to), s(s), t(t) {}
	inline bool operator < (const node &a) const {
		return (double)s / t > (double)a.s / a.t;
	}
} ;

std::priority_queue<node> q;
std::vector<int> edge[MAXN];

int n, x, y, val;
int w[MAXN], deg[MAXN], father[MAXN], sum[MAXN], size[MAXN], fa[MAXN];
bool able[MAXN];

inline void add_edge(int x, int y) {
	edge[x].push_back(y), edge[y].push_back(x);
}

inline void read_in() {
	R(n);
	for (int i = 1; i < n; ++i) R(x), R(y), add_edge(x, y);
	for (int i = 1; i <= n; ++i) R(w[i]), R(able[i]);
}

inline void dfs(int cur, int fa) {
	deg [cur] = 0;
	for (int p = 0; p < edge[cur].size(); ++p) {
		int v = edge[cur][p];
		if (v != fa) father[v] = cur, dfs(v, cur), deg[cur]++;
	}
}

inline int get_father(int x) {
	return (fa[x] == x) ? (x) : (fa[x] = get_father(fa[x]));
}

inline void solve() {
	long long ans = 0;
	for (int i = 1; i <= n; ++i) {
		if (able[i]) {
			dfs(i, 0);
			long long ret = 0;
			while (!q.empty()) q.pop();
			for (int j = 1; j <= n; ++j) {
				if (j != i) q.push(node(j, w[j], 1));
				sum[j] = w[j], size[j] = 1, ret += w[j], fa[j] = j;
			}
			while (!q.empty()) {
				node temp = q.top();
				int cur = q.top().to;
				q.pop();
				if (get_father(cur) != cur || size[cur] != temp.t) continue ;
				int fa = get_father(father[cur]);
//				std::cout << "cur == " << cur << " " << fa << '\n';
//				std::cout << size[cur] << " " << sum[cur] << " " << size[fa] << " " << sum[fa] << '\n';
				ret += (long long) size [fa] * sum [cur], :: fa [cur] = fa;
				size[fa] += size[cur], sum[fa] += sum[cur];
				if (fa != i) q.push(node(fa, sum[fa], size[fa]));
			}
			ans = std::max(ans, ret);
		}
	}
	std::cout << ans;
}

int main() {
	freopen("xmastree2.in", "r", stdin);
	freopen("xmastree2.out", "w", stdout);
	read_in();
	solve();
	return 0;
}