weighted lca

rainbou-kpr · Aug 6, 2024 · d9a61d2 · d9a61d2
1 parent 865343f
commit d9a61d2
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Showing 2 changed files with 50 additions and 3 deletions.
diff --git a/cpp/tree.hpp b/cpp/tree.hpp
@@ -135,7 +135,6 @@ struct RootedTree : private Tree<Cost> {
  using Tree<Cost>::operator[];
  using Tree<Cost>::edges;
  using Tree<Cost>::shortest_path;
- using Tree<Cost>::Tree;
 
  int root; //!< 根
  std::vector<Edge> par; //!< 親へ向かう辺
@@ -262,7 +261,6 @@ struct DoublingClimbTree : private RootedTree<Cost> {
  using RootedTree<Cost>::operator[];
  using RootedTree<Cost>::edges;
  using RootedTree<Cost>::shortest_path;
- using RootedTree<Cost>::RootedTree;
  using RootedTree<Cost>::root;
  using RootedTree<Cost>::par;
  using RootedTree<Cost>::child;
@@ -296,6 +294,34 @@ struct DoublingClimbTree : private RootedTree<Cost> {
  build();
  }
 
+ /**
+ * @brief 親の頂点のリストから根が0のダブリング済み根付き木を構築するコンストラクタ
+ * 
+ * @param par_ 頂点0以外の親の頂点のリスト
+ * @param padding = -1 parの頂点番号をいくつずらすか
+ */
+ DoublingClimbTree(const std::vector<int>& par_, int padding = -1) : RootedTree<Cost>(par_, padding) {
+ build();
+ }
+ /**
+ * @brief Treeからダブリング済み根付き木を構築するコンストラクタ(コピー)
+ *
+ * @param tree Tree
+ * @param root 根
+ */
+ DoublingClimbTree(const Tree<Cost>& tree, int root) : RootedTree<Cost>(tree, root) {
+ build();
+ }
+ /**
+ * @brief Treeからダブリング済み根付き木を構築するコンストラクタ(ムーブ)
+ *
+ * @param tree Tree
+ * @param root 根
+ */
+ DoublingClimbTree(Tree<Cost>&& tree, int root) : RootedTree<Cost>(std::move(tree), root) {
+ build();
+ }
+
  /**
  * @brief 頂点uからk回を根の方向に遡った頂点
  * 
@@ -321,7 +347,6 @@ struct DoublingClimbTree : private RootedTree<Cost> {
  int lca(int u, int v) const {
  if(this->unweighted_depth[u] > this->unweighted_depth[v]) std::swap(u, v);
  v = climb(v, this->unweighted_depth[v] - this->unweighted_depth[u]);
- if(this->unweighted_depth[u] > this->unweighted_depth[v]) u = climb(u, this->unweighted_depth[u] - this->unweighted_depth[v]);
  if(u == v) return u;
  for(int i = h - 1; i >= 0; i--) {
  int nu = doubling_par[i][u];

diff --git a/test/yukicoder-898.test.cpp b/test/yukicoder-898.test.cpp
@@ -0,0 +1,22 @@
+#define PROBLEM "https://yukicoder.me/problems/no/898"
+
+#include "../cpp/tree.hpp"
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+int main() {
+ int n; cin >> n;
+ Tree<ll> tr(n); tr.read(0, true);
+ DoublingClimbTree<ll> dct(tr, 0);
+ int q; cin >> q;
+ while(q--) {
+ array<int, 3> xyz;
+ for(int i = 0; i < 3; i++) cin >> xyz[i];
+ int lca01 = dct.lca(xyz[0], xyz[1]);
+ int lca02 = dct.lca(xyz[0], xyz[2]);
+ int lca12 = dct.lca(xyz[1], xyz[2]);
+ int center = lca01 ^ lca02 ^ lca12;
+ cout << dct.dist(xyz[0], center) + dct.dist(xyz[1], center) + dct.dist(xyz[2], center) << endl;
+ }
+}