我就不应该在NOIP两天前打这种题的..

#include <bits/stdc++.h>
#define int long long
#define maxn 800005
using namespace std;
int n, m, dep[maxn], sz[maxn], fa[maxn], son[maxn], tp[maxn], tot, cnt, to[maxn], head[maxn], id[maxn], w[maxn];
int tag[maxn];
struct node {
	int sum, maxk, mink;
}ansn[maxn << 1];
struct node1 {
	int v, pre, w, num;
}e[maxn << 1];
void dfs1(int now, int fat) {
	dep[now] = dep[fat] + 1;
	sz[now] = 1;
	fa[now] = fat;
	int t = -1;
	for(int i = head[now];i;i = e[i].pre) {
		int v = e[i].v;
		if(v != fat) {
			dfs1(v, now);
			sz[now] += sz[v];
			if(sz[v] > t) {
				t = sz[v];
				son[now] = v;
			}
		}
	}
}
void dfs2(int now, int top, int last, int lastpre) {
	tp[now] = top;
	id[now] = ++cnt;
	w[cnt] = last;
	to[lastpre] = now;
	for(int i = head[now];i;i = e[i].pre) {
		int v = e[i].v;
		if(v == son[now]) dfs2(v, top, e[i].w, e[i].num);
		else if(v != fa[now]) dfs2(v, v, e[i].w, e[i].num);
	}
}
void add(int u, int v, int w, int p) {
	e[++tot].v = v;
	e[tot].w = w;
	e[tot].pre = head[u];
	e[tot].num = p;
	head[u] = tot;
}
int ls(int x) {
	return x << 1;
}
int rs(int x) {
	return x << 1 | 1;
}
void pushup(int x) {
	ansn[x].sum = ansn[ls(x)].sum + ansn[rs(x)].sum;
	ansn[x].maxk = max(ansn[ls(x)].maxk, ansn[rs(x)].maxk);
	ansn[x].mink = min(ansn[ls(x)].mink, ansn[rs(x)].mink);
}
void build(int p, int l, int r) {
	int mid = (l + r) >> 1;
	if(l == r) {
//		cout << l << " " << p << " " << w[l] << endl;
		ansn[p].sum = w[l];
		ansn[p].maxk = w[l];
		ansn[p].mink = w[l];
		return;
	}
	build(ls(p), l, mid);
	build(rs(p), mid + 1, r);
	pushup(p);
}
void f(int p, int l, int r, int k) {
	if(k == -1) {
		ansn[p].sum = -ansn[p].sum;
		int pq = ansn[p].maxk;
		ansn[p].maxk = -ansn[p].mink;
		ansn[p].mink = -pq;
		tag[p] = -1;
		return;
	}
}
void pushdown(int p, int l, int r) {
	int mid = (l + r) >> 1;
	f(ls(p), l, mid, tag[p]);
	f(rs(p), mid + 1, r, tag[p]);
	tag[p] = 0;
}
void change(int nl, int nr, int l, int r, int p, int k) {
	int mid = (l + r) >> 1;
	if(l == r) {
		ansn[p].sum = k;
		ansn[p].maxk = k;
		ansn[p].mink = k;
		return;
	}
	pushdown(p, l, r);
	if(nl <= mid) change(nl, nr, l, mid, ls(p), k);
	else change(nl, nr, mid + 1, r, rs(p), k);
	pushup(p);
}
void Natur(int nl, int nr, int l, int r, int p) {
	int mid = (l + r) >> 1;
	if(nl <= l && r <= nr) {
		tag[p] = -1;
		ansn[p].sum = -ansn[p].sum;
		int pq = ansn[p].maxk;
		ansn[p].maxk = -ansn[p].mink;
		ansn[p].mink = -pq;
		return;
	}
	pushdown(p, l, r);
	if(nl <= mid) Natur(nl, nr, l, mid, ls(p));
	if(nr > mid) Natur(nl, nr, mid + 1, r, rs(p));
	pushup(p);
}
int querym(int nl, int nr, int l, int r, int p) {
	int res = -2147483647, mid = (l + r) >> 1;
	if(nl <= l && r <= nr) return ansn[p].maxk;
	pushdown(p, l, r);
	if(nl <= mid) res = max(res, querym(nl, nr, l, mid, ls(p)));
	if(nr > mid) res = max(res, querym(nl, nr, mid + 1, r, rs(p)));
	return res;
}
int queryi(int nl, int nr, int l, int r, int p) {
	int res = 2147483647, mid = (l + r) >> 1;
	if(nl <= l && r <= nr) return ansn[p].mink;
	pushdown(p, l, r);
	if(nl <= mid) res = min(res, queryi(nl, nr, l, mid, ls(p)));
	if(nr > mid) res = min(res, queryi(nl, nr, mid + 1, r, rs(p)));
	return res;
}
int querys(int nl, int nr, int l, int r, int p) {
//	cout << nl << " " << nr << " " << l << " " << r << " " << p << endl;
	int res = 0, mid = (l + r) >> 1;
	if(nl <= l && r <= nr) {
//		cout << p << " " << ansn[p].sum << "!!!!!" << endl;+

		return ansn[p].sum;
	}
	pushdown(p, l, r);
	if(nl <= mid) res += querys(nl, nr, l, mid, ls(p));
	if(nr > mid) res += querys(nl, nr, mid + 1, r, rs(p));
//	cout << res << endl;
	return res;
}
void cNatur(int x, int y) {
	while(tp[x] != tp[y]) {
		if(dep[tp[x]] < dep[tp[y]]) swap(x, y);
		Natur(id[tp[x]], id[x], 1, n, 1);
		x = fa[tp[x]];
	}
	if(dep[x] > dep[y]) swap(x, y);
	Natur(id[x] + 1, id[y], 1, n, 1);
	return;
}
int querymax(int x, int y) {
	int res = -2147483647;
	while(tp[x] != tp[y]) {
		if(dep[tp[x]] < dep[tp[y]]) swap(x, y);
		res = max(res, querym(id[tp[x]], id[x], 1, n, 1));
		x = fa[tp[x]];
	}
	if(dep[x] > dep[y]) swap(x, y);
	res = max(res, querym(id[x] + 1, id[y], 1, n, 1));
	return res;
}
int querymin(int x, int y) {
	int res = 2147483647;
	while(tp[x] != tp[y]) {
	
		if(dep[tp[x]] < dep[tp[y]]) swap(x, y);
		res = min(res, queryi(id[tp[x]], id[x], 1, n, 1));
		x = fa[tp[x]];
	}
//		cout << x << " " << y << " " << tp[x] << " " << tp[y] << endl;
	if(dep[x] > dep[y]) swap(x, y);
	res = min(res, queryi(id[x] + 1, id[y], 1, n, 1));
	return res;
}
int querysum(int x, int y) {
	int res = 0;
	while(tp[x] != tp[y]) {
//		cout << x << " " << y << " " << tp[x] << " " << tp[y] << endl;
		if(dep[tp[x]] < dep[tp[y]]) swap(x, y);
		res += querys(id[tp[x]], id[x], 1, n, 1);
//		cout << x << " " << y << " " << res << endl;
		x = fa[tp[x]];
	}
	if(dep[x] > dep[y]) swap(x, y);
//	cout << id[x] + 1 << " " << id[y] << endl;
	res += querys(id[x] + 1, id[y], 1, n, 1);
//	cout << x << " " << y << " " << res << endl;
	return res;
}
signed main() {
	scanf("%lld", &n);
	for(int i = 1;i <= n - 1;i++) {
		int u, v, w;
		scanf("%lld%lld%lld", &u, &v, &w);
		u ++, v ++;
		add(u, v, w, i);
		add(v, u, w, i);
	}
	dfs1(1, 0);
	dfs2(1, 1, 0, 0);
	build(1, 1, n);
	scanf("%lld", &m);
	for(int i = 1;i <= m;i++) {
		int x, y;
		char mps[15];
		cin >> mps;
		if(mps[0] == 'C') {//change
			scanf("%lld%lld", &x, &y);
			int p = to[x];
//			cout << p << endl;
			change(id[p], id[p], 1, n, 1, y);
		}
		else if(mps[0] == 'N') {//*=-1
			scanf("%lld%lld", &x, &y);
			x ++, y ++;
			cNatur(x, y);
		}
		else if(mps[1] == 'U') {//sum
			scanf("%lld%lld", &x, &y);
			x ++, y ++;
			printf("%lld\n", querysum(x, y));
		}
		else if(mps[1] == 'A') {//max
			scanf("%lld%lld", &x, &y);
			x ++, y ++;
			printf("%lld\n", querymax(x, y));
		}
		else {//min
			scanf("%lld%lld", &x, &y);
			x ++, y ++;
			printf("%lld\n", querymin(x, y));
//			querymin(x, y);
		}
	}
}

不指望有人能帮我调出来, 但还是希望有人能调调..