题目链接：传送门
线段树维护每个点的k,t,d 当做懒标记来维护 这就需要对懒标记的理解了
#include <bits/stdc++.h> #define A 300010 using namespace std; typedef long long ll; namespace Seg { struct node {int l, r, k, d, w, f;}tree[A]; void build(int k, int l, int r) { tree[k].l = l; tree[k].r = r; if (l == r) return; int m = (l + r) >> 1; build(k << 1, l, m); build(k << 1 | 1, m + 1, r); } void down(int k) { tree[k << 1].w += tree[k].w + tree[k << 1].k * tree[k].d; tree[k << 1 | 1].w += tree[k].w + tree[k << 1 | 1].k * tree[k].d; tree[k << 1].k += tree[k].k; tree[k << 1 | 1].k += tree[k].k; tree[k << 1].d += tree[k].d; tree[k << 1 | 1].d += tree[k].d; tree[k].w = tree[k].k = tree[k].d = 0; } void change1(int k, int l, int r, int val) { if (tree[k].l >= l and tree[k].r <= r) {tree[k].k += val; return;} int m = (tree[k].l + tree[k].r) >> 1; down(k); if (l <= m) change1(k << 1, l, r, val); if (r > m) change1(k << 1 | 1, l, r, val); } void change2(int k, int l, int r, int val) { if (tree[k].l >= l and tree[k].r <= r) {tree[k].d += val; tree[k].w += tree[k].k * val; return;} int m = (tree[k].l + tree[k].r) >> 1; down(k); if (l <= m) change2(k << 1, l, r, val); if (r > m) change2(k << 1 | 1, l, r, val); } int ask(int k, int pos) { if (tree[k].l == tree[k].r) return tree[k].w; int m = (tree[k].l + tree[k].r) >> 1; down(k); if (pos <= m) return ask(k << 1, pos); else return ask(k << 1 | 1, pos); } } int dfn[A]; namespace Cut { struct node {int next, to;}e[A]; int head[A], num; int siz[A], fa[A], dep[A], son[A], top[A], cnt; void add(int fr, int to) {e[++num].next = head[fr]; e[num].to = to; head[fr] = num; swap(fr, to); e[++num].next = head[fr]; e[num].to = to; head[fr] = num;} void prepare(int fr) { siz[fr] = 1; for (int i = head[fr]; i; i = e[i].next) { int ca = e[i].to; if (ca == fa[fr]) continue; fa[ca] = fr; dep[ca] = dep[fr] + 1; prepare(ca); siz[fr] += siz[ca]; if (siz[ca] > siz[son[fr]]) son[fr] = ca; } } void dfs(int fr, int tp) { dfn[fr] = ++cnt; top[fr] = tp; if (son[fr]) dfs(son[fr], tp); for (int i = head[fr]; i; i = e[i].next) { int ca = e[i].to; if (ca == fa[fr] or ca == son[fr]) continue; dfs(ca, ca); } } void change1(int x, int y, int val) { while (top[x] != top[y]) { if (dep[top[x]] < dep[top[y]]) swap(x, y); Seg::change1(1, dfn[top[x]], dfn[x], val); x = fa[top[x]]; } if (dep[x] > dep[y]) swap(x, y); Seg::change1(1, dfn[x], dfn[y], val); } void change2(int x, int y, int val) { while (top[x] != top[y]) { if (dep[top[x]] < dep[top[y]]) swap(x, y); Seg::change2(1, dfn[top[x]], dfn[x], val); x = fa[top[x]]; } if (dep[x] > dep[y]) swap(x, y); Seg::change2(1, dfn[x], dfn[y], val); } } int n, m, a, b, opt; int main(int argc, char const *argv[]) { cin >> n; for (int i = 2; i <= n; i++) scanf("%d%d", &a, &b), Cut::add(a, b); cin >> m; Cut::prepare(1); Cut::dfs(1, 1); Seg::build(1, 1, n); while (m--) { scanf("%d", &opt); if (opt == 1) scanf("%d%d", &a, &b), Cut::change1(1, a, b); if (opt == 2) scanf("%d%d", &a, &b), Cut::change2(1, a, b); if (opt == 3) scanf("%d", &a), printf("%d\n", Seg::ask(1, dfn[a])); } }