SS21

Author: yani5752000

preInReconstruct/pom.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.mycompany</groupId>
+    <artifactId>preInReconstruct</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+</project>

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

@@ -0,0 +1,54 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package com.mycompany.preinreconstruct;
+
+import java. util. ArrayList;
+
+/**
+ *
+ * @author asadp
+ */
+public class PreInReconstruct {
+    class Node {
+        int item;
+        Node left,right;
+
+        public Node(int key) {
+        item = key;
+        left = right = null;
+        }
+    }
+    ArrayList<Node> nodes = new ArrayList<Node>();
+    void preInReconstruct(int preOrder[], int inOrder[]){
+        Node root = new Node(preOrder[0]);
+        int index = 0;
+        for(int i = 0; i < inOrder.length; i++){
+            if(inOrder[i] == root.item){
+                index = i;
+                break;
+            }
+        }
+        int inOrderLeft[] = new int[index];
+        int inOrderRight[] = new int[inOrder.length - index -1];
+        for(int i = 0; i < index; i++){
+            inOrderLeft[i] = inOrder[i];
+         }
+        for(int i = 0; i < inOrder.length - index -1; i++){
+            inOrderRight[i] = inOrder[i + index];
+         }
+        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];
+         }
+        for(int i = 0; i < inOrder.length - index -1; i++){
+            preOrderRight[i] = inOrder[i + index + 1];
+         }
+        
+        root.left = preOrderLeft[0];
+        
+    }
+}