Data commit

Task/Eertree/Ruby/eertree.rb

@@ -0,0 +1,79 @@
+class Node
+    def initialize(length, edges = {}, suffix = 0)
+        @length = length
+        @edges = edges
+        @suffix = suffix
+    end
+
+    attr_reader :length
+    attr_reader :edges
+    attr_accessor :suffix
+end
+
+EVEN_ROOT = 0
+ODD_ROOT = 1
+
+def eertree(s)
+    tree = [
+        Node.new(0, {}, ODD_ROOT),
+        Node.new(-1, {}, ODD_ROOT)
+    ]
+    suffix = ODD_ROOT
+    s.each_char.with_index { |c, i|
+        n = suffix
+        k = 0
+        loop do
+            k = tree[n].length
+            b = i - k - 1
+            if b >= 0 and s[b] == c then
+                break
+            end
+            n = tree[n].suffix
+        end
+        if tree[n].edges.key?(c) then
+                suffix = tree[n].edges[c]
+            next
+        end
+        suffix = tree.length
+        tree << Node.new(k + 2)
+        tree[n].edges[c] = suffix
+        if tree[suffix].length == 1 then
+            tree[suffix].suffix = 0
+            next
+        end
+        loop do
+            n = tree[n].suffix
+            b = i - tree[n].length - 1
+            if b >= 0 and s[b] == c then
+                break
+            end
+        end
+        tree[suffix].suffix = tree[n].edges[c]
+    }
+    return tree
+end
+
+def subPalindromes(tree)
+    s = []
+
+    children = lambda { |n,p,f|
+        for c,v in tree[n].edges
+            m = tree[n].edges[c]
+            p = c + p + c
+            s << p
+            f.call(m, p, f)
+        end
+    }
+
+    children.call(0, '', children)
+
+    for c,n in tree[1].edges
+        s << c
+        children.call(n, c, children)
+    end
+
+    return s
+end
+
+tree = eertree("eertree")
+print subPalindromes(tree), "\n"