@[FiraCode](/user/528430)
build函数有问题。
A了。
```cpp
#include <bits/stdc++.h>
using namespace std;
#define int long long
using ll = long long;
const int N = 100010;
int n, m;
int a[N];
vector<int> e[N];
int dfn[N], top[N], dep[N], fa[N], sz[N], son[N], idx;
int na[N];
void dfs1(int u, int f) {
dep[u] = dep[f] + 1;
fa[u] = f;
sz[u] = 1;
for (auto v : e[u]) {
if (v == f) continue;
dfs1(v, u);
sz[u] += sz[v];
if (!son[u] || sz[son[u]] < sz[v])
son[u] = v;
}
}
void dfs2(int u, int topf) {
dfn[u] = ++idx;
na[idx]=a[u];
top[u] = topf;
if (son[u])
dfs2(son[u], topf);
for (auto v : e[u]) {
if (v == son[u] || v == fa[u]) continue;
dfs2(v, v);
}
}
struct Node {
int l, r;
ll sum, add;
}tr[N * 4];
void pushup(int u) {
tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
}
void pushdown(int u) {
tr[u << 1].add += tr[u].add;
tr[u << 1 | 1].add += tr[u].add;
tr[u << 1].sum += (tr[u << 1].r - tr[u << 1].l + 1) * tr[u].add;
tr[u << 1 | 1].sum += (tr[u << 1 | 1].r - tr[u << 1 | 1].l + 1) * tr[u].add;
tr[u].add = 0;
}
void build(int u, int l, int r) {
tr[u] = {l, r};
if (l == r) {
tr[u].sum = na[l];
return;
}
int mid = (l + r) >> 1;
build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
pushup(u);
}
void modify(int u, int l, int r, int d) {
if (tr[u].l >= l && tr[u].r <= r) {
tr[u].add += d;
tr[u].sum += (tr[u].r - tr[u].l + 1) * d;
return;
}
pushdown(u);
int mid = (tr[u].l + tr[u].r) >> 1;
if (l <= mid) modify(u << 1, l, r, d);
if (r > mid) modify(u << 1 | 1, l, r, d);
pushup(u);
}
ll query(int u, int l, int r) {
if (tr[u].l >= l && tr[u].r <= r) {
return tr[u].sum;
}
pushdown(u);
int mid = (tr[u].l + tr[u].r) >> 1;
ll res = 0;
if (l <= mid) res += query(u << 1, l, r);
if (r > mid) res += query(u << 1 | 1, l, r);
return res;
}
ll query(int u, int v) {
ll ans = 0;
while (top[u] != top[v]) {
if (dep[top[u]] < dep[top[v]]) swap(u, v);
ans += query(1, dfn[top[u]], dfn[u]);
u = fa[top[u]];
}
if (dep[u] > dep[v]) swap(u, v);
ans += query(1, dfn[u], dfn[v]);
return ans;
}
signed main() {
scanf("%lld%lld", &n, &m);
for (int i = 1; i <= n; ++i)
scanf("%lld", &a[i]);
for (int i = 1; i < n; ++i) {
int u, v;
scanf("%lld%lld", &u, &v);
e[u].push_back(v);
e[v].push_back(u);
}
dfs1(1, 0);
dfs2(1, 1);
build(1, 1, n);
while (m--) {
int opt;
scanf("%lld", &opt);
if (opt == 1) {
int x, d;
scanf("%lld%lld", &x, &d);
modify(1, dfn[x], dfn[x], d);
}else if (opt == 2) {
int x, d;
scanf("%lld%lld", &x, &d);
modify(1, dfn[x], dfn[x] + sz[x] - 1, d);
}else {
int x;
scanf("%lld", &x);
printf("%lld\n", query(1, x));
}
}
return 0;
}
```
by XHY20180718 @ 2022-12-31 12:07:25
@[xiehuiying](/user/399475) 非常感谢。解决了我好几天的困惑。
by FiraCode @ 2022-12-31 12:26:42