From 16fac4caf81869aad756918c68f851c0c0ee153d Mon Sep 17 00:00:00 2001
From: Algy <algy@ubuntu.ubuntu-domain>
Date: Mon, 16 Dec 2019 03:46:33 +0900
Subject: [PATCH] Rem algorithm

---
 src/cca.cpp |  6 +++---
 src/cca.h   | 55 ++++++++++++++++++++---------------------------------
 2 files changed, 24 insertions(+), 37 deletions(-)

diff --git a/src/cca.cpp b/src/cca.cpp
index 7493c43..a3f103a 100644
--- a/src/cca.cpp
+++ b/src/cca.cpp
@@ -71,12 +71,12 @@ namespace cca {
                     int left_index = index - 1, up_index = index - W;
 
                     if (left_cluster_no == cluster_no) {
-                        cc_set.add_single(left_index, index);
-                        if (assignment[up_index] == cluster_no && cc_set.parents[left_index] != cc_set.parents[up_index]) {
+                        cc_set.merge(left_index, index);
+                        if (assignment[up_index] == cluster_no) {
                             cc_set.merge(left_index, up_index);
                         }
                     } else if (assignment[up_index] == cluster_no) {
-                        cc_set.add_single(up_index, index);
+                        cc_set.merge(up_index, index);
                     }
                     left_cluster_no = cluster_no;
                 }
diff --git a/src/cca.h b/src/cca.h
index b88056d..ccbe7e6 100644
--- a/src/cca.h
+++ b/src/cca.h
@@ -22,51 +22,38 @@ namespace cca {
                 parents[i] = i;
             }
         }
-
-    private:
-        inline void set_root(tree_node_t root, tree_node_t node) {
-            for (tree_node_t i = node; root < i; ) {
-                int parent = parents[i];
-                parents[i] = root;
-                i = parent;
-            }
-        }
-    public:
         inline tree_node_t add() {
             tree_node_t c = size++;
             parents.push_back(c);
             return c;
         }
+
         inline void clear() {
             parents.clear();
             size = 0;
         }
 
-        inline int find_root(tree_node_t node) {
-            tree_node_t parent = parents[node];
-            while (parent < node) {
-                node = parent;
-                parent = parents[parent];
+        inline void merge(tree_node_t node_i, tree_node_t node_j) {
+            tree_node_t root_x = node_i, root_y = node_j;
+            while (parents[root_x] != parents[root_y]) {
+                if (parents[root_x] > parents[root_y]) {
+                    if (root_x == parents[root_x]) {
+                        parents[root_x] = parents[root_y];
+                        break;
+                    }
+                    tree_node_t z = parents[root_x];
+                    parents[root_x] = parents[root_y];
+                    root_x = z;
+                } else {
+                    if (root_y == parents[root_y]) {
+                        parents[root_y] = parents[root_x];
+                        break;
+                    }
+                    tree_node_t z = parents[root_y];
+                    parents[root_y] = parents[root_x];
+                    root_y = z;
+                }
             }
-            return node;
-        }
-        inline tree_node_t find(tree_node_t node) {
-            tree_node_t root = find_root(node);
-            set_root(root, node);
-            return root;
-        }
-
-        inline tree_node_t merge(tree_node_t node_i, tree_node_t node_j) {
-            tree_node_t root = find_root(node_i);
-            tree_node_t root_j = find_root(node_j);
-            if (root > root_j) root = root_j;
-            set_root(root, node_j);
-            set_root(root, node_i);
-            return root;
-        }
-
-        inline void add_single(tree_node_t node_i, tree_node_t single_j) {
-            parents[single_j] = parents[node_i];
         }
         std::unique_ptr<ComponentSet> flatten();
     };