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OI-codes/S2OJ/1172/1172.cpp

146 lines
3.0 KiB
C++

#include <cstdio>
#include <vector>
const int N = 200005;
int n, q, u, v, op, a[N];
std::vector<int> g[N];
// Heavy Path Decomposition
int cnt, id[N], rid[N], fa[N], dep[N], son[N], siz[N], top[N];
void dfs1(int, int);
void dfs2(int, int);
void modify_tree(int, int);
int query_point(int);
// Segment Tree
void pushdown(int);
void build(int, int, int);
void modify(int, int, int, int);
int query(int, int);
int main() {
scanf("%d%d", &n, &q);
for (int i = 1; i <= n; i++) {
scanf("%d", a + i);
}
for (int i = 1; i < n; i++) {
scanf("%d%d", &u, &v);
g[u].push_back(v);
g[v].push_back(u);
}
dfs1(1, 1);
dfs2(1, 1);
build(1, 1, n);
while (q--) {
scanf("%d%d", &op, &u);
if (op == 1) {
scanf("%d", &v);
modify_tree(u, v);
} else {
printf("%d\n", query_point(u));
}
}
return 0;
}
// === Heavy Path Decomposition ===
void dfs1(int u, int f) {
fa[u] = f;
dep[u] = dep[f] + 1;
siz[u] = 1;
for (int v : g[u]) {
if (v == f) continue;
dfs1(v, u);
siz[u] += siz[v];
if (siz[son[u]] < siz[v]) son[u] = v;
}
}
void dfs2(int u, int t) {
id[u] = ++cnt;
rid[cnt] = u;
if (!son[u]) return;
dfs2(son[u], t);
for (int v : g[u]) {
if (v == fa[u]) continue;
if (v == son[u]) continue;
dfs2(v, v);
}
}
inline void modify_tree(int u, int d) {
modify(1, id[u], id[u] + siz[u] - 1, d * ((dep[u] & 1) ? 1 : -1));
}
inline int query_point(int x) {
return query(1, id[x]);
}
// === Segment Tree ===
struct node {
int l, r, d;
node()
: l(0),
r(0),
d(0) {}
node(int _l, int _r)
: l(_l),
r(_r),
d(0) {}
} tr[N << 2];
void pushdown(int u) {
node &root = tr[u], &left = tr[u << 1], &right = tr[u << 1 | 1];
if (!root.d) return;
if (left.l == left.r) {
left.d += root.d * ((dep[rid[left.l]] & 1) ? 1 : -1);
} else {
left.d += root.d;
}
if (right.l == right.r) {
right.d += root.d * ((dep[rid[right.l]] & 1) ? 1 : -1);
} else {
right.d += root.d;
}
root.d = 0;
}
void build(int u, int l, int r) {
tr[u] = node(l, r);
if (l == r) {
tr[u].d = a[rid[l]];
return;
}
int mid = l + r >> 1;
build(u << 1, l, mid);
build(u << 1 | 1, mid + 1, r);
}
void modify(int u, int l, int r, int d) {
if (l <= tr[u].l && tr[u].r <= r) {
if (tr[u].l == tr[u].r) {
tr[u].d += d * ((dep[rid[tr[u].l]] & 1) ? 1 : -1);
} else {
tr[u].d += d;
}
return;
}
int mid = tr[u].l + tr[u].r >> 1;
pushdown(u);
if (l <= mid) modify(u << 1, l, r, d);
if (r > mid) modify(u << 1 | 1, l, r, d);
}
int query(int u, int x) {
if (tr[u].l == tr[u].r) return tr[u].d;
int mid = tr[u].l + tr[u].r >> 1;
pushdown(u);
if (x <= mid) return query(u << 1, x);
return query(u << 1 | 1, x);
}