add splaytree feature to tree

README.md

@@ -29,6 +29,7 @@ Implementation of various data structures and algorithms in Go.
  - [AVLTree](#avltree)
  - [BTree](#btree)
  - [BinaryHeap](#binaryheap)
+ - [SplayTree](#spalytree)
 - [Functions](#functions)
  - [Comparator](#comparator)
  - [Iterator](#iterator)
@@ -846,6 +847,100 @@ func main() {
 }
 ```
 
+#### SplayTree
+
+<b>A polymorphic splay tree implementation in Go(lang)</b>
+
+splay is defined around the <code>SplayTree</code> interface: 
+
+ type SplayTree interface {
+ SetRoot(n *Node)
+ GetRoot() *Node
+ Ord(key1, key2 interface{}) int
+ }
+
+Your <code>SplayTree</code> implementation must contain a <code>root *Node</code> where
+
+ type Node struct {
+ key interface{}
+ value interface{}
+ parent *Node
+ left *Node
+ right *Node
+ }
+
+<code>SetRoot</code> and <code>GetRoot</code> are the getter and setter for root, and <code>Ord</code> is a method for
+comparing keys must return 0 if key1 < key2, 1 if key1 == key2, or 2 if
+key1 > key2 (for whatever definitions of <, ==, and > apply to your key type).
+
+Here's an example assuming we have the splay directory in the same directory as
+our project (a very similar example is given in <i>example.go</i>):
+
+ package main
+
+ import (
+ "./splay"
+ "fmt"
+ "unicode/utf8"
+ )
+
+ type Tree struct {
+ root *splay.Node
+ }
+
+ func (T *Tree) SetRoot(n *splay.Node) {
+ T.root = n
+ }
+
+ func (T *Tree) GetRoot() *splay.Node {
+ return T.root
+ }
+
+ // This Splay Tree will use strings as keys and strings as values
+ // It returns 0, 1, or 2 based on the lexical comparison of the key strings
+ func (T *Tree) Ord(key1, key2 interface{}) int {
+ for i := 0; i < len(key1.(string)); {
+ c1, j := utf8.DecodeRuneInString(key1.(string)[i:])
+ c2, _ := utf8.DecodeRuneInString(key2.(string)[i:])
+ if c1 < c2 {
+ return 0
+ } else if c1 > c2 {
+ return 2
+ }
+ i += j
+ }
+ if len(key1.(string)) < len(key2.(string)) {
+ return 0
+ } else if len(key1.(string)) == len(key2.(string)) {
+ return 1
+ } else {
+ return 2
+ }
+ }
+
+ func main() {
+ T := new(Tree)
+
+ splay.Insert(T, "hello", "world")
+ splay.Insert(T, "foo", "bar")
+ splay.Insert(T, "what's your name", "buddy?")
+ splay.Insert(T, "Goku says", "Kamehameha")
+ err := splay.Insert(T, "foo", "foo")
+ fmt.Println(err)
+
+ v := splay.Find(T, "Goku says")
+ fmt.Println(v)
+
+ splay.Print(T)
+
+ splay.Delete(T, "foo")
+ err = splay.Delete(T, "foo")
+ fmt.Println(err)
+
+ splay.Print(T)
+ }
+
+
 ## Functions
 
 Various helper functions used throughout the library.