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BinaryTree2.java
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258 lines (229 loc) · 6.56 KB
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/*/Q1.: diameter of a tree(No of nodes int longest path bw two leaves)
//approach 1 time comlexity=O(n^2)
public class BinaryTree2 {
static class Node {
int data;
Node left;
Node right;
Node(int data) {
this.data = data;
this.left = null;
this.right = null;
}
}
public static int height(Node root){
if(root == null){
return 0;
}
int lh= height(root.left);
int rh= height(root.right);
return Math.max(lh, rh)+1;
}
public static int diameter(Node root){
if(root == null){
return 0;
}
int leftDiam = diameter(root.left);
int leftht = height(root.left);
int rightDiam = diameter(root.right);
int rightht = height(root.right);
int selfDiam = leftht + rightht+1;
return Math.max(selfDiam,Math.max(leftDiam,rightDiam));
}
public static void main(String[] args) {
// 1
// / \
// 2 3
// / \ / \
// 4 5 6 7
Node root = new Node(1);
root.left= new Node(2);
root.right= new Node(3);
root.left.left= new Node(4);
root.left.right= new Node(5);
root.right.left= new Node(6);
root.right.right= new Node(7);
System.out.println(diameter(root));
}
}
*/
/*/approach 2 time complexity =O(n)
public class BinaryTree2 {
static class Node {
int data;
Node left;
Node right;
Node(int data) {
this.data = data;
this.left = null;
this.right = null;
}
}
static class Info{
int diam;
int ht;
public Info(int diam,int ht){
this.diam=diam;
this.ht=ht;
}
}
public static Info diameter(Node root){
if(root == null){
return new Info(0, 0);
}
Info leftInfo = diameter(root.left);
Info rightInfo = diameter(root.right);
int diam = Math.max(Math.max(leftInfo.diam,rightInfo.diam),leftInfo.ht+rightInfo.ht+1);
int ht= Math.max(leftInfo.ht,rightInfo.ht)+1;
return new Info(diam, ht);
}
public static void main(String[] args) {
// 1
// / \
// 2 3
// / \ / \
// 4 5 6 7
Node root = new Node(1);
root.left= new Node(2);
root.right= new Node(3);
root.left.left= new Node(4);
root.left.right= new Node(5);
root.right.left= new Node(6);
root.right.right= new Node(7);
System.out.println(diameter(root).diam);
System.out.println(diameter(root).ht);
}
}
*/
/*/Q2.: Subtree of another tree || Tc=O(n)
public class BinaryTree2 {
static class Node {
int data;
Node left;
Node right;
Node(int data) {
this.data = data;
this.left = null;
this.right = null;
}
}
public static boolean isIdentical(Node node,Node subroot){
if(node == null && subroot == null){
return true;
}else if(node ==null || subroot == null || node.data!=subroot.data){
return false;
}
if(!isIdentical(node.left,subroot.left)){
return false;
}
if(!isIdentical(node.right, subroot.right)){
return false;
}
return true;
}
public static boolean isSubtree(Node root,Node subroot){
if(root == null){
return false;
}
if(root.data == subroot.data){
if(isIdentical(root,subroot)){
return true;
}
}
return isSubtree(root.left, subroot)|| isSubtree(root.right,subroot);
}
public static void main(String[] args) {
// 1
// / \
// 2 3
// / \ / \
// 4 5 6 7
Node root = new Node(1);
root.left= new Node(2);
root.right= new Node(3);
root.left.left= new Node(4);
root.left.right= new Node(5);
root.right.left= new Node(6);
root.right.right= new Node(7);
// 2
// / \
// 4 5
Node subRoot = new Node (2);
subRoot.left = new Node(4);
subRoot.right= new Node(5);
System.out.println(isSubtree(root, subRoot));
}
}
*/
//Top view of a tree
import java.util.*;
import java.util.LinkedList;
public class BinaryTree2 {
static class Node {
int data;
Node left;
Node right;
Node(int data) {
this.data = data;
this.left = null;
this.right = null;
}
}
static class Info{
Node node;
int hd;
public Info(Node node,int hd){
this.node=node;
this.hd=hd;
}
}
public static void topView(Node root){
//level order
Queue<Info>q =new LinkedList<>();
HashMap<Integer,Node> map = new HashMap<>();
int min = 0,max=0;
q.add(new Info(root, 0));
q.add(null);
while(!q.isEmpty()){
Info curr = q.remove();
if(curr==null){
if(q.isEmpty()){
break;
}else{
q.add(null);
}
}else{
if(!map.containsKey(curr.hd)){//first time hd is occur
map.put(curr.hd, curr.node);
}
if(curr.node.left!=null){
q.add(new Info(curr.node.left,curr.hd-1));
min = Math.min(min,curr.hd-1);
}
if(curr.node.right!=null){
q.add(new Info(curr.node.right,curr.hd+1));
max= Math.max(max, curr.hd+1);
}
}
}
for(int i=min;i<=max;i++){
System.out.print(map.get(i).data +" ");
}
System.out.println();
}
public static void main(String[] args) {
// 1
// / \
// 2 3
// / \ / \
// 4 5 6 7
Node root = new Node(1);
root.left= new Node(2);
root.right= new Node(3);
root.left.left= new Node(4);
root.left.right= new Node(5);
root.right.left= new Node(6);
root.right.right= new Node(7);
topView(root);
}
}