mirror of
https://git.sb/baoshuo/OI-codes.git
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209 lines
4.7 KiB
C++
209 lines
4.7 KiB
C++
#include <iostream>
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#include <string>
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#include <vector>
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using std::cin;
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using std::cout;
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using std::endl;
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const int N = 100005;
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int n, u, v, w, k, a[N];
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std::string op;
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std::pair<int, int> t[N];
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std::vector<int> g[N];
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// Heavy Path Decomposition
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int cnt, b[N], id[N], fa[N], dep[N], siz[N], son[N], top[N];
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void dfs1(int, int);
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void dfs2(int, int);
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void modify_path(int, int, int);
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void change_path(int, int, int);
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int query_path(int, int);
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// Segment Tree
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void pushup(int);
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void pushdown(int);
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void build(int, int, int);
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void modify(int, int, int, int);
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void change(int, int, int, int);
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int query(int, int, int);
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int main() {
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cin >> n;
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for (int i = 1; i < n; i++) {
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cin >> t[i].first >> t[i].second >> a[i];
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g[t[i].first].push_back(t[i].second);
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g[t[i].second].push_back(t[i].first);
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}
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dfs1(1, 1);
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dfs2(1, 1);
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build(1, 1, n);
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for (int i = 1; i < n; i++) {
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if (dep[t[i].first] < dep[t[i].second]) std::swap(t[i].first, t[i].second);
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modify(1, id[t[i].first], id[t[i].first], a[i]);
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}
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while (cin >> op, op != "Stop") {
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if (op == "Change") {
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cin >> k >> w;
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change(1, id[t[k].first], id[t[k].first], w);
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} else if (op == "Cover") {
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cin >> u >> v >> w;
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change_path(u, v, w);
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} else if (op == "Add") {
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cin >> u >> v >> w;
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modify_path(u, v, w);
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} else {
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cin >> u >> v;
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cout << query_path(u, v) << endl;
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}
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}
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return 0;
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}
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// === Heavy Path Decomposition ===
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void dfs1(int u, int f) {
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fa[u] = f;
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dep[u] = dep[f] + 1;
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siz[u] = 1;
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for (int v : g[u]) {
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if (v == f) continue;
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dfs1(v, u);
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siz[u] += siz[v];
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if (siz[son[u]] < siz[v]) son[u] = v;
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}
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}
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void dfs2(int u, int t) {
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id[u] = ++cnt;
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top[u] = t;
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if (!son[u]) return;
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dfs2(son[u], t);
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for (int v : g[u]) {
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if (v == fa[u]) continue;
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if (v == son[u]) continue;
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dfs2(v, v);
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}
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}
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void modify_path(int u, int v, int d) {
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while (top[u] != top[v]) {
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if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
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modify(1, id[top[u]], id[u], d);
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u = fa[top[u]];
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}
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if (dep[u] < dep[v]) std::swap(u, v);
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modify(1, id[son[v]], id[u], d);
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}
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void change_path(int u, int v, int d) {
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while (top[u] != top[v]) {
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if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
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change(1, id[top[u]], id[u], d);
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u = fa[top[u]];
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}
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if (dep[u] < dep[v]) std::swap(u, v);
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change(1, id[son[v]], id[u], d);
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}
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int query_path(int u, int v) {
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int res = 0;
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while (top[u] != top[v]) {
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if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
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res = std::max(res, query(1, id[top[u]], id[u]));
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u = fa[top[u]];
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}
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if (dep[u] < dep[v]) std::swap(u, v);
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res = std::max(res, query(1, id[son[v]], id[u]));
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return res;
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}
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// == Segment Tree ===
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struct node {
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int l, r, m, da, dc;
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node()
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: l(0),
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r(0),
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m(0),
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da(0),
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dc(-1) {}
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node(int _l, int _r)
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: l(_l),
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r(_r),
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m(0),
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da(0),
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dc(-1) {}
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} tr[N << 2];
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inline void pushup(int u) {
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tr[u].m = std::max(tr[u << 1].m, tr[u << 1 | 1].m);
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}
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inline void pushdown(int u) {
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node &root = tr[u], &left = tr[u << 1], &right = tr[u << 1 | 1];
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if (root.dc != -1) {
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left.m = right.m = root.dc;
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left.da = right.da = 0;
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left.dc = right.dc = root.dc;
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root.dc = -1;
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}
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left.m += root.da;
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left.da += root.da;
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right.m += root.da;
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right.da += root.da;
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root.da = 0;
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}
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void build(int u, int l, int r) {
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tr[u] = node(l, r);
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if (l == r) {
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tr[u].m = b[l];
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return;
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}
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int mid = l + r >> 1;
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build(u << 1, l, mid);
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build(u << 1 | 1, mid + 1, r);
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pushup(u);
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}
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void modify(int u, int l, int r, int d) {
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if (l <= tr[u].l && tr[u].r <= r) {
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tr[u].m += d;
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tr[u].da += d;
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return;
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}
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int mid = tr[u].l + tr[u].r >> 1;
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pushdown(u);
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if (l <= mid) modify(u << 1, l, r, d);
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if (r > mid) modify(u << 1 | 1, l, r, d);
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pushup(u);
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}
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void change(int u, int l, int r, int d) {
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if (l <= tr[u].l && tr[u].r <= r) {
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tr[u].m = d;
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tr[u].da = 0;
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tr[u].dc = d;
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return;
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}
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int mid = tr[u].l + tr[u].r >> 1;
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pushdown(u);
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if (l <= mid) change(u << 1, l, r, d);
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if (r > mid) change(u << 1 | 1, l, r, d);
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pushup(u);
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}
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int query(int u, int l, int r) {
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if (l <= tr[u].l && tr[u].r <= r) return tr[u].m;
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pushdown(u);
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int mid = tr[u].l + tr[u].r >> 1;
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int res = 0;
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if (l <= mid) res = std::max(res, query(u << 1, l, r));
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if (r > mid) res = std::max(res, query(u << 1 | 1, l, r));
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return res;
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}
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