From b3bbb77bf83e4345354587d770e0eb58f0486a33 Mon Sep 17 00:00:00 2001
From: Bruno Freitas Tissei <bft15@inf.ufpr.br>
Date: Sat, 3 Feb 2018 12:20:21 -0200
Subject: [PATCH] Add kruskal
Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>
---
graph/kruskal.cpp | 39 ++++++++++++++++++++++++++++++++++++++
structure/disjoint_set.cpp | 14 +++++++-------
2 files changed, 46 insertions(+), 7 deletions(-)
create mode 100644 graph/kruskal.cpp
diff --git a/graph/kruskal.cpp b/graph/kruskal.cpp
new file mode 100644
index 0000000..ca5dd37
--- /dev/null
+++ b/graph/kruskal.cpp
@@ -0,0 +1,39 @@
+/**
+ * Kruskal
+ *
+ * Complexity (Time): O (m log n)
+ * Complexity (Space): O(m)
+ *
+ * #include <structure/disjoint_set>
+ *
+ * OBS: * = return maximum spanning tree
+ */
+
+vector<iii> mst;
+vector<iii> edges;
+
+bool cmp(iii a, iii b) {
+ return a.se < b.se;
+ //* return a.se > b.se
+}
+
+int kruskal() {
+ sort(edges.begin(), edges.end(), cmp);
+
+ int size = 0;
+ for (int i = 0; i < MAX; i++)
+ make_set(i);
+
+ for (int i = 0; i < edges.size(); i++) {
+ int pu = find_set(edges[i].fi.fi);
+ int pv = find_set(edges[i].fi.se);
+
+ if (pu != pv) {
+ mst.pb(edges[i]);
+ size += edges[i].se;
+ union_set(pu, pv);
+ }
+ }
+
+ return size;
+}
diff --git a/structure/disjoint_set.cpp b/structure/disjoint_set.cpp
index 2f5af9e..37f3ff6 100644
--- a/structure/disjoint_set.cpp
+++ b/structure/disjoint_set.cpp
@@ -2,8 +2,8 @@
* Disjoint-set
*
* Complexity (Time): O(1)
- * makeset -> O(1)
- * find -> O(a(n))
+ * make_set -> O(1)
+ * find_set -> O(a(n))
* union_set -> O(a(n))
* Complexity (Space): O(n)
*/
@@ -13,24 +13,24 @@ int rank[MAX];
int sz[MAX];
// Initialize element x
-void makeset(int x) {
+void make_set(int x) {
par[x] = x;
rank[x] = 0;
sz[x] = 1;
}
// Return set index from element x
-int find(int x) {
+int find_set(int x) {
if (par[x] != x)
- par[x] = find(par[x]);
+ par[x] = find_set(par[x]);
return par[x];
}
// Make x and y belong to the same set
void union_set(int x, int y) {
- int xroot = find(x);
- int yroot = find(y);
+ int xroot = find_set(x);
+ int yroot = find_set(y);
if (xroot == yroot)
return;
--
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