From 2d8171b2b334f9712d3de162269607ce784d419d Mon Sep 17 00:00:00 2001
From: Nimrod Rak <nimrod.rak@mail.huji.ac.il>
Date: Tue, 12 Oct 2021 10:18:41 +0300
Subject: [PATCH 1/2] added disjoint sets data structure

---
 .../disjoint_sets/disjoint_sets.rb            | 37 +++++++++++++++++++
 data_structures/disjoint_sets/node.rb         | 20 ++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 data_structures/disjoint_sets/disjoint_sets.rb
 create mode 100644 data_structures/disjoint_sets/node.rb

diff --git a/data_structures/disjoint_sets/disjoint_sets.rb b/data_structures/disjoint_sets/disjoint_sets.rb
new file mode 100644
index 0000000..2d71185
--- /dev/null
+++ b/data_structures/disjoint_sets/disjoint_sets.rb
@@ -0,0 +1,37 @@
+require "./data_structures/disjoint_sets/node.rb"
+
+class DisjointSets
+    def make_set(d)
+        Node.new(d)
+    end
+
+    def find_set(x)
+        raise ArgumentError unless x.class <= Node
+        x.parent=(find_set(x.parent)) unless x.parent == x
+        x.parent
+    end
+
+    def union_set(x, y)
+        px = find_set(x)
+        py = find_set(y)
+        return if px == py
+        if px.rank > py.rank
+            py.parent = px
+        elsif py.rank > px.rank
+            px.parent = py
+        else
+            px.parent = py
+            py.rank += 1
+        end
+    end
+end
+
+ds = DisjointSets.new
+one = ds.make_set(1)
+two = ds.make_set(2)
+three = ds.make_set(3)
+ds.union_set(one, two)
+puts ds.find_set(one) == ds.find_set(two) # should be true
+ds.union_set(one, three)
+puts ds.find_set(two) == ds.find_set(three) # should be true
+puts one.rank + two.rank + three.rank == 1 # should be true
\ No newline at end of file
diff --git a/data_structures/disjoint_sets/node.rb b/data_structures/disjoint_sets/node.rb
new file mode 100644
index 0000000..d1cdca5
--- /dev/null
+++ b/data_structures/disjoint_sets/node.rb
@@ -0,0 +1,20 @@
+class Node
+    attr_accessor :data, :parent, :rank
+    def initialize(data)
+        @data = data
+        @parent = self
+        @rank = 0
+    end
+    def parent
+        @parent
+    end
+    def parent=(parent)
+        @parent = parent;
+    end
+    def rank
+        @rank
+    end
+    def rank=(rank)
+        @rank = rank
+    end
+end
\ No newline at end of file

From 87db7cf633bd3d155370d5731db452e9fbaf53c1 Mon Sep 17 00:00:00 2001
From: Nimrod Rak <nimrod.rak@mail.huji.ac.il>
Date: Tue, 12 Oct 2021 10:21:38 +0300
Subject: [PATCH 2/2] fixed importing issue

---
 .../disjoint_sets/disjoint_sets.rb            | 21 ++++++++++++++++++-
 data_structures/disjoint_sets/node.rb         | 20 ------------------
 2 files changed, 20 insertions(+), 21 deletions(-)
 delete mode 100644 data_structures/disjoint_sets/node.rb

diff --git a/data_structures/disjoint_sets/disjoint_sets.rb b/data_structures/disjoint_sets/disjoint_sets.rb
index 2d71185..d9624fe 100644
--- a/data_structures/disjoint_sets/disjoint_sets.rb
+++ b/data_structures/disjoint_sets/disjoint_sets.rb
@@ -1,4 +1,23 @@
-require "./data_structures/disjoint_sets/node.rb"
+class Node
+    attr_accessor :data, :parent, :rank
+    def initialize(data)
+        @data = data
+        @parent = self
+        @rank = 0
+    end
+    def parent
+        @parent
+    end
+    def parent=(parent)
+        @parent = parent;
+    end
+    def rank
+        @rank
+    end
+    def rank=(rank)
+        @rank = rank
+    end
+end
 
 class DisjointSets
     def make_set(d)
diff --git a/data_structures/disjoint_sets/node.rb b/data_structures/disjoint_sets/node.rb
deleted file mode 100644
index d1cdca5..0000000
--- a/data_structures/disjoint_sets/node.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-class Node
-    attr_accessor :data, :parent, :rank
-    def initialize(data)
-        @data = data
-        @parent = self
-        @rank = 0
-    end
-    def parent
-        @parent
-    end
-    def parent=(parent)
-        @parent = parent;
-    end
-    def rank
-        @rank
-    end
-    def rank=(rank)
-        @rank = rank
-    end
-end
\ No newline at end of file