Added find() to RadixTree class

Author: scalls

Radix-Tree/RadixTree.swift

@@ -124,7 +124,7 @@ class RadixTree {
 	func insert(_ str: String) -> Bool {
 		//Account for a blank input
 		if str == "" {
-			return true
+			return false
 		}
 		//Account for an empty tree
 		if root.children.count == 0 {
@@ -135,7 +135,6 @@ class RadixTree {
 		var currEdge = root
 		while (true) {
 			var found = false
-			var i = 0
 			if currEdge.children.count == 0 {
 				let newEdge = Edge(searchStr)
 				currEdge.children.append(newEdge)
@@ -190,7 +189,6 @@ class RadixTree {
 					return true
 				}
 				//They don't share a prefix (go to next child)
-				i += 1
 			}
 			if (!found) {
 				//No children share a prefix, so create a new child
@@ -202,6 +200,64 @@ class RadixTree {
 		}
 	}
 
+	func find(_ str: String) -> Bool {
+		//A radix tree always contains the empty string
+		if str == "" {
+			return true
+		}
+		//If there are no children then the string cannot be in the tree
+		else if root.children.count == 0 {
+			return false
+		}
+		var searchStr = str
+		var currEdge = root
+		while (true) {
+			var found = false
+			for c in currEdge.children {
+				//First check if the search string and the child's label are equal
+				//  if so the string is in the tree, return true
+				if searchStr == c.label {
+					return true
+				}
+				//If that is not true, find the shared string b/t the search string
+				//  and the label
+				var shared = sharedPrefix(searchStr, c.label)
+				//If the shared string is equal to the label, update the curent node
+				//  and run it back
+				if shared == c.label {
+					currEdge = c
+					var tempIndex = searchStr.startIndex
+					for _ in 1...shared.characters.count {
+						tempIndex = tempIndex.successor()
+					}
+					searchStr = searchStr.substringFromIndex(tempIndex)
+					found = true
+					break
+				}
+				//If the shared string is empty, go to the next children
+				else if shared.characters.count == 0 {
+					continue
+				}
+				//If the search string and the child's label only share some characters,
+				//  the string is not in the tree, return false
+				else if shared[shared.startIndex] == c.label[c.label.startIndex] &&
+				  shared.characters.count < c.label.characters.count {
+				  	return false
+				}
+			}
+			if !found {
+				return false
+			}
+		}
+		//Start at the root
+			//If a child's label is a prefix of the search string
+			//  Cut the prefix off of the search string and 
+			//    start looking through that child's children
+			//If a child's label == searchStr, return true
+
+		//If none of the children's labels are a prefix of the search string
+	}
+
 	func printTree() {
 		root.printRoot()
 	}

Radix-Tree/main.swift

@@ -1,29 +1,13 @@
 var radix = RadixTree()
-var radix2 = RadixTree()
 var radixWiki = RadixTree()
 
-print("-------------------------------------------------")
-radix.printTree()
-print("--------------------------------------------------")
-radix.insert( "courting" )
-radix.printTree()
-print("-------------------------------------------------")
-radix.insert( "coral" )
-radix.printTree()
-print("--------------------------------------------------")
-radix.insert( "courted" )
-radix.printTree()
-print("---------------------------------------------------")
-print( radix.insert( "corals") )
-radix.printTree()
-
-print( radixWiki.insert("romanus") )
-print( radixWiki.insert("rubicundus") )
-print( radixWiki.insert("rubicon") )
-print( radixWiki.insert("romane") )
-print( radixWiki.insert("ruber") )
-print( radixWiki.insert("rubens") )
-print( radixWiki.insert("romulus") )
+radixWiki.insert("romanus")
+radixWiki.insert("rubicundus")
+radixWiki.insert("rubicon")
+radixWiki.insert("romane")
+radixWiki.insert("ruber")
+radixWiki.insert("rubens")
+radixWiki.insert("romulus")
 radixWiki.insert("start")
 radixWiki.insert("shoot")
 radixWiki.insert("shit")
@@ -42,24 +26,9 @@ radixWiki.insert("courted")
 
 radixWiki.insert("rubicunduses")
 
-print("PRINT TEST-------------------------------")
-radixWiki.printTree()
-
-let h = radix.height()
-let h2 = radix2.height()
-let hwiki = radixWiki.height()
-print("Height of tree: \(h)")
-print("height of second tree: \(h2)")
-print("Height of wikipedia tree: \(hwiki)")
-
-print(radixWiki.root.level())
-print(radixWiki.root.children[0].level())
-print(radixWiki.root.children[0].children[0].level())
-print(radixWiki.root.children[0].children[0].children[0].level())
-
-print("\t\t\t\t\t\ttest")
-print("PRINT TEST-------------------------------")
 radixWiki.printTree()
 
-print("PRINT TEST-------------------------------")
-radix.printTree()
+print("FIND TESTS")
+print(radixWiki.find("courts"))
+print(radixWiki.find("rubicunduses"))
+print(radixWiki.find(""))