SS22

Author: yani5752000

.gitignore

@@ -12,3 +12,4 @@
 /quickSort/target/
 /bTree/target/
 /bSearchTree/target/
+/preInReconstruct/target/

preInReconstruct/src/main/java/com/mycompany/preinreconstruct/PreInReconstruct.java

@@ -12,6 +12,7 @@
  * @author asadp
  */
 public class PreInReconstruct {
+    static ArrayList<Node> treeNodes = new ArrayList<Node>();
     class Node {
         int item;
         Node left,right;
@@ -21,34 +22,80 @@ public Node(int key) {
         left = right = null;
         }
     }
-    ArrayList<Node> nodes = new ArrayList<Node>();
+    Node treeNodeForItem(int key){
+        for(Node node : treeNodes){
+            if(node.item == key){
+                return node;
+            }
+        }
+        Node node = new Node(key);
+        treeNodes.add(node);
+        return node;
+    }
+    
     void preInReconstruct(int preOrder[], int inOrder[]){
-        Node root = new Node(preOrder[0]);
+        if(preOrder.length == 0 || inOrder.length == 0){
+            return;
+        }
+        Node root = treeNodeForItem(preOrder[0]);
         int index = 0;
         for(int i = 0; i < inOrder.length; i++){
             if(inOrder[i] == root.item){
                 index = i;
                 break;
             }
         }
+        System.out.println("index: " + index);
         int inOrderLeft[] = new int[index];
         int inOrderRight[] = new int[inOrder.length - index -1];
         for(int i = 0; i < index; i++){
             inOrderLeft[i] = inOrder[i];
+            System.out.print(inOrderLeft[i] + " ");
          }
+        System.out.println("");
         for(int i = 0; i < inOrder.length - index -1; i++){
-            inOrderRight[i] = inOrder[i + index];
+            inOrderRight[i] = inOrder[i + index + 1];
+            System.out.print(inOrderRight[i] + " ");
          }
+        System.out.println("");
         int preOrderLeft[] = new int[index];
         int preOrderRight[] = new int[inOrder.length - index -1];
         for(int i = 0; i < index; i++){
             preOrderLeft[i] = preOrder[i + 1];
+            System.out.print(preOrderLeft[i] + " ");
          }
+        System.out.println("");
         for(int i = 0; i < inOrder.length - index -1; i++){
-            preOrderRight[i] = inOrder[i + index + 1];
+            preOrderRight[i] = preOrder[i + index + 1];
+            System.out.print(preOrderRight[i] + " ");
          }
+        System.out.println("");
+        if(preOrderLeft.length > 0){
+            Node left = treeNodeForItem(preOrderLeft[0]);
+            root.left = left;
+            System.out.println("left: " + left.item);
+        }
+        if(preOrderRight.length > 0){
+            Node right = treeNodeForItem(preOrderRight[0]);
+            root.right = right;
+            System.out.println("right: " + right.item);
+        }
 
-        root.left = preOrderLeft[0];
-        
+        preInReconstruct(preOrderLeft, inOrderLeft);
+        preInReconstruct(preOrderRight, inOrderRight);
+    }
+    void printTreeNodes(){
+        for(Node node: treeNodes){
+            System.out.println("Node item: " + node.item 
+            + " left: " + (node.left == null? "null": node.left.item)
+            + " right: " + (node.right == null? "null": node.right.item));
+        }
+    }
+    public static void main(String[] args) {
+        PreInReconstruct pIR = new PreInReconstruct();
+        int preOrder[] = {-1};
+        int inOrder[] = {-1};
+        pIR.preInReconstruct(preOrder, inOrder);
+        pIR.printTreeNodes();
     }
 }