【BZOJ 3531】【SDOI 2014】旅行 树链剖分

#include<cstdio>
#include<cstring>
#include<algorithm>
#define read(x) x=getint()
#define N 100003
using namespace std;
inline int getint() {int k = 0, fh = 1; char c = getchar(); for(; c < ‘0‘ || c > ‘9‘; c = getchar()) if (c == ‘-‘) fh = -1; for(; c >= ‘0‘ && c <= ‘9‘; c = getchar()) k = k * 10 + c - ‘0‘; return k * fh;}
struct Tree {
	int l, r, ma, sm;
} T[4000010];
struct G {
	int nxt, to;
} E[N << 1];
int root[N], point[N], cnt = 0, n, q, W[N], C[N], sz[N], son[N], up[N];
int deep[N], fa[N], watch[N];
inline void ins(int x, int y) {E[++cnt].nxt = point[x]; E[cnt].to = y; point[x] = cnt;}
inline void _(int x) {
	sz[x] = 1;
	for(int tmp = point[x]; tmp; tmp = E[tmp].nxt) {
		int v = E[tmp].to;
		if (v == fa[x]) continue;
		fa[v] = x;
		deep[v] = deep[x] + 1;
		_(v);
		if (sz[v] > sz[son[x]])
			son[x] = v;
		sz[x] += sz[v];
	}
}
inline void __(int x) {
	watch[x] = ++cnt;
	if (!son[x]) return;
	up[son[x]] = up[x];
	__(son[x]);
	for(int tmp =point[x]; tmp; tmp = E[tmp].nxt) {
		int v = E[tmp].to;
		if (v == fa[x] || v == son[x]) continue;
		up[v] = v;
		__(v);
	}
}

inline void pushup(int pos) {
	T[pos].sm = T[T[pos].l].sm + T[T[pos].r].sm;
	T[pos].ma = max(T[T[pos].l].ma, T[T[pos].r].ma);
}
inline void update(int &pos, int l, int r, int to, int num) {
	if (pos == 0) pos = ++cnt;
	if (l == r) {T[pos].ma = T[pos].sm = num; return;}
	int mid = (l + r) >> 1;
	if (to <= mid) update(T[pos].l, l, mid, to, num);
	else update(T[pos].r, mid + 1, r, to, num);
	pushup(pos);
}
inline int Qsum(int pos, int L, int R, int l, int r) {
	if (L <= l && r <= R) return T[pos].sm;
	int mid = (l + r) >> 1, s = 0;
	if (L <= mid) s += Qsum(T[pos].l, L, R, l, mid);
	if (R > mid) s += Qsum(T[pos].r, L, R, mid + 1, r);
	return s;
}
inline int Qmax(int pos, int L, int R, int l, int r) {
	if (L <= l && r <= R) return T[pos].ma;
	int mid = (l + r) >> 1, s = 0;
	if (L <= mid) s = Qmax(T[pos].l, L, R, l, mid);
	if (R > mid) s = max(s, Qmax(T[pos].r, L, R, mid + 1, r));
	return s;
}

inline int Max(int CC, int x, int y) {
	int ans = 0;
	while (up[x] != up[y]) {
		if (deep[up[x]] < deep[up[y]]) swap(x, y);
		ans = max(ans, Qmax(root[CC], watch[up[x]], watch[x], 1, n));
		x = fa[up[x]];
	}
	if (deep[x] > deep[y]) swap(x, y);
	ans = max(ans, Qmax(root[CC], watch[x], watch[y], 1, n));
	return ans;
}
inline int Sum(int CC, int x, int y) {
	int ans = 0;
	while (up[x] != up[y]) {
		if (deep[up[x]] < deep[up[y]]) swap(x, y);
		ans += Qsum(root[CC], watch[up[x]], watch[x], 1, n);
		x = fa[up[x]];
	}
	if (deep[x] > deep[y]) swap(x, y);
	ans += Qsum(root[CC], watch[x], watch[y], 1, n);
	return ans;
}

int main() {
	read(n); read(q);
	for(int i = 1; i <= n; ++i)
		read(W[i]), read(C[i]);
	int u, v;
	for(int i = 1; i < n; ++i) {
		read(u); read(v);
		ins(u, v); ins(v, u);
	}
	_(1);
	up[1] = 1;
	cnt = 0;
	__(1);
	cnt = 0;
	for(int i = 1; i <= n; ++i)
		update(root[C[i]], 1, n, watch[i], W[i]);
	char c; int x, y;
	for(int i = 1; i <= q; ++i) {
		for(c = getchar(); c < ‘A‘ || c > ‘Z‘; c = getchar());
		if (c == ‘C‘) {
			c = getchar(); read(x); read(y);
			if (c == ‘C‘) {
				update(root[C[x]], 1, n, watch[x], 0);
				C[x] = y;
				update(root[C[x]], 1, n, watch[x], W[x]);
			} else {
				update(root[C[x]], 1, n, watch[x], y);
				W[x] = y;
			}
		} else {
			c = getchar(); read(x); read(y);
			if (c == ‘S‘)
				printf("%d\n", Sum(C[x], x, y));
			else
				printf("%d\n", Max(C[x], x, y));
		}
	}
	return 0;
}