树剖求调
查看原帖
树剖求调
716260
SegmentTree_楼主2023/12/30 13:18
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define lid (id << 1)
#define rid (id << 1 | 1)
const int N = 2e5 + 5;
struct node{
	int l, r;
	ll sum;
}tr[N << 2];
int n, q;
int head[N << 1], nxt[N << 1], val[N << 1], to[N << 1], cccnnnttt, U[N], V[N], val1[N];
int fa[N], dep[N], hson[N], siz[N], cnt, rnk[N], dfn[N], top[N];
int a[N];
void pushup(int id){
	tr[id].sum = tr[lid].sum + tr[rid].sum;
}
void build(int id, int l, int r){
	tr[id].l = l;
	tr[id].r = r;
	if (l == r){
		tr[id].sum = a[l];
		return;
	}
	int mid = (l + r) >> 1;
	build(lid, l, mid);
	build(rid, mid + 1, r);
	pushup(id);
}
void modify(int id, int x, ll y){
	if (tr[id].l == tr[id].r){
		tr[id].sum = y;
		return;
	}
	int mid = (tr[id].l + tr[id].r) >> 1;
	if (x <= mid) modify(lid, x, y);
	else modify(rid, x, y);
	pushup(id);
}
ll qsum(int id, int l, int r){
	if(tr[id].l>r||tr[id].r<l)return 0;
	if (l <= tr[id].l && tr[id].r <= r) return tr[id].sum;
	int mid = (tr[id].l + tr[id].r) >> 1;
	if (r <= mid) return qsum(lid, l, r);
	else if (l > mid) return qsum(rid, l, r);
	else return qsum(lid, l, mid) + qsum(rid, mid + 1, r);
}
void add1(int u, int v, int w){
	to[++cccnnnttt] = v;
	val[cccnnnttt] = w;
	nxt[cccnnnttt] = head[u];
	head[u] = cccnnnttt;
}
void dfs1(int u, int f){
	int maxson = -1;
	siz[u] = 1;
	hson[u] = -1;
	for (int i = head[u];i;i = nxt[i]){
		int v = to[i];
		if (v == f) return;
		fa[v] = u;
		dep[v] = dep[u] + 1;
		val1[v] = val[i];
		dfs1(v, u);
		siz[u] += siz[v];
		if (siz[v] > maxson){
			maxson = siz[v];
			hson[u] = v;
		}
	}
}
void dfs2(int u, int t){
	top[u] = t;
	dfn[u] = ++cnt;
	rnk[cnt] = u;
	a[cnt] = val1[u];
	if (hson[u] == -1) return;
	dfs2(hson[u], t);
	for (int i = head[u];i;i = nxt[i]){
		int v = to[i];
		if (v == hson[u] || v == fa[u]) continue;
		dfs2(v, v);
	}
}
ll qrangesum(int x, int y){
	ll ans = 0;
	while (top[x] != top[y]){
		if (dep[top[x]] < dep[top[y]]) swap(x, y);
		ans += qsum(1, dfn[top[x]], dfn[x]);
		x = fa[top[x]];
	}
	if (dep[x] > dep[y]) swap(x, y);
	ans += qsum(1, dfn[x] + 1, dfn[y]);
	return ans;
}
void modifynode(int x, ll k){
	modify(1, dfn[x], k);
}
int main(){
	cin >> n;
	for (int i = 1;i < n;i++){
		int u, v, w;
		cin >> u >> v >> w;
		add1(u, v, w);
		add1(v, u, w);
		U[i] = u;
		V[i] = v;
	}
	dep[1] = 1;
	dfs1(1, 0);
	dfs2(1, 1);
	build(1, 1, n);
	cin >> q;
	while (q--){
		int op, a, b;
		cin >> op >> a >> b;
		if (op == 1){
			int u1 = U[a], v1 = V[a];
			if (dep[v1] < dep[u1]) swap(v1, u1);
			modifynode(v1, b);
		}
		else{
			cout << qrangesum(a, b) << '\n';
		}
	}
	return 0;
} 
2023/12/30 13:18
加载中...