first draft

Author: lrvideckis

library/dsu/kruskal_tree.hpp …brary/dsu/kruskal_tree_linear_height.hpplibrary/dsu/kruskal_tree.hpp renamed to library/dsu/kruskal_tree_linear_height.hpp library/dsu/kruskal_tree.hpp renamed to library/dsu/kruskal_tree_linear_height.hpp

@@ -0,0 +1,15 @@
+#pragma once
+//! https://mzhang2021.github.io/cp-blog/kruskal/
+//! @time O(n log n)
+//! @space O(n)
+struct kr_tree {
+  int id;
+  vi p;
+  vector<vi> adj;
+  kr_tree(int n): id(n), p(2 * n, -1), adj(2 * n) {}
+  int f(int v) { return p[v] < 0 ? v : p[v] = f(p[v]); }
+  bool join(int u, int v) {
+    if ((u = f(u)) == (v = f(v))) return 0;
+    return adj[p[u] = p[v] = id++] = {u, v}, 1;
+  }
+};

library/dsu/kruskal_tree_log_height.hpp

@@ -1,7 +1,7 @@
 #define PROBLEM \
   "https://onlinejudge.u-aizu.ac.jp/problems/ALDS1_12_A"
 #include "../template.hpp"
-#include "../../../library/dsu/kruskal_tree.hpp"
+#include "../../../library/dsu/kruskal_tree_linear_height.hpp"
 int main() {
   cin.tie(0)->sync_with_stdio(0);
   int n;

tests/library_checker_aizu_tests/dsu/kruskal_tree_aizu.test.cpp

@@ -2,7 +2,7 @@
   "https://judge.yosupo.jp/problem/minimum_spanning_tree"
 #include "../template.hpp"
 #include "../../../library/dsu/line_tree.hpp"
-#include "../../../library/dsu/kruskal_tree.hpp"
+#include "../../../library/dsu/kruskal_tree_linear_height.hpp"
 int main() {
   cin.tie(0)->sync_with_stdio(0);
   int n, m;