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Deletion BST in Java #1331

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Deletion BST in Java #1331

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aba2639
seach, insert, traveral binary sub tree in java
phuuthanh-dev Feb 15, 2024
8439e23
delete in bst
phuuthanh-dev Feb 15, 2024
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213 changes: 213 additions & 0 deletions Deletion In BST/Deletebymerging.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,213 @@
/*
* 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 deletionbymerging;

class Node {

int info;
Node left, right;

Node(int x) {
info = x;
left = right = null;
}
}

class BSTree {

Node root;

BSTree() {
root = null;
}

boolean isEmpty() {
return (root == null);
}

void insert(int x) {
if (root == null) {
root = new Node(x);
return;
}
Node f = null, p = root;
while (p != null) {
if (p.info == x) {
System.out.println(" The key " + x + " already exists, no insertion.");
return;
}
if (x < p.info) {
f = p;
p = p.left;
} else {
f = p;
p = p.right;
}
}
if (x < f.info) {
f.left = new Node(x);
} else {
f.right = new Node(x);
}
}

//return a node which has key = given key in the tree p
public Node search(Node p, int key) {
if (p == null) {
return null;
}
if (p.info == key) {
return p;
} else if (p.info > key) {
return search(p.left, key);
} else {
return search(p.right, key);
}
}

public void deleteByMerging(int x) {
Node p = search(root, x);
if (p == null) {
System.out.println("Key " + x + " does not exists, deletion failed");
return;
}
//find f is father of p
Node f = null, q = root;
while (q != p) {
f = q;
if (q.info > p.info) {
q = q.left;
} else {
q = q.right;
}
}
//1- p has no child
if (p.left == null && p.right == null) {
if (f == null) {
root = null;
} else if (f.left == p) {
f.left = null;
} else {
f.right = null;
}
} //2- p has the left child only
else if (p.left != null && p.right == null) {
if (f == null) {
root = p.left;
} else if (f.left == p) {
f.left = p.left;
} else {
f.right = p.left;
}
} //3- p has the right child only
else if (p.left == null && p.right != null) {
if (f == null) {
root = p.right;
} else if (f.left == p) {
f.left = p.right;
} else {
f.right = p.right;
}
} //4- p has both left and right children
else if (p.left != null && p.right != null) {
//find q is the largest node on the left child of p (q is the right
//child with the largest key of the left child of p)
q = p.left;
Node t = null;
while (q.right != null) {
t = q;
q = q.right;
}
//merge the right child of p into q
Node rp = p.right;
q.right = rp;
if (f == null) {
root = p.left;
} else if (f.left == p) {
f.left = p.left;
} else {
f.right = p.left;
}
}
}

void visit(Node p) {
if (p == null) {
return;
}
System.out.print(" " + p.info);
}

void preOrder(Node p) {
if (p == null) {
return;
}
visit(p);
preOrder(p.left);
preOrder(p.right);
}

void inOrder(Node p) {
if (p == null) {
return;
}
inOrder(p.left);
visit(p);
inOrder(p.right);
}

void postOrder(Node p) {
if (p == null) {
return;
}
postOrder(p.left);
postOrder(p.right);
visit(p);
}

void addArray(int[] a) {
for (int i = 0; i < a.length; i++) {
insert(a[i]);
}
}
}

public class Main {

public static void main(String[] args) {
BSTree t = new BSTree();
System.out.println(" BST after insertion (3 5 1 5 9 8 2):");
int[] a = {3, 5, 1, 5, 9, 8, 2};
t.addArray(a);

/* 3 1
/ \ \
1 5 2
\ \ \
2 9 5
/ \
8 9
- Pre-order : 3 1 2 5 9 8 / - Pre-order : 1 2 5 9 8
- In-order : 1 2 3 5 8 9 8 - In-order : 1 2 5 8 9
- Post-order: 2 1 8 9 5 3 - Post-order: 8 9 5 2 1
*/
System.out.print(" - Pre-order traverse:");
t.preOrder(t.root);
System.out.print("\n - In-order traverse:");
t.inOrder(t.root);
System.out.print("\n - Post-order traverse: ");
t.postOrder(t.root);
System.out.print("\n Ater deleting 3:");
t.deleteByMerging(3);
System.out.print("\n - Pre-order traverse:");
t.preOrder(t.root);
System.out.print("\n - In-order traverse:");
t.inOrder(t.root);
System.out.print("\n - Post-order traverse: ");
t.postOrder(t.root);
System.out.println();
}
}
164 changes: 164 additions & 0 deletions Deletion In BST/deletebycopying.java
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Original file line number Diff line number Diff line change
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/*
* 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 deletionbycopying;
class Node {
int info;
Node left,right;
Node(int x) {info=x;left=right=null;}
}

class BSTree {
Node root;
BSTree() {root=null;}
boolean isEmpty() {return(root==null);}

void insert(int x) {
if(root==null) {root = new Node(x); return;}
Node f=null, p=root;
while(p!=null) {
if(p.info==x) {
System.out.println(" The key " + x
+ " already exists, no insertion.");
return;
}
if(x<p.info) {f=p;p=p.left;}
else {f=p;p=p.right;}
}
if(x<f.info)
f.left=new Node(x);
else
f.right=new Node(x);
}

void copyDele(int x) {
if(root==null) {
System.out.println("The tree is empty, no deletion.");
return;
}
//find f is father of p
Node f=null, p=root;
while(p!=null) {
if(p.info==x) break;//found key x
if(x<p.info) {f=p;p=p.left;}
else {f=p;p=p.right;}
}
if(p==null) {//not found key x
System.out.println("The key " + x + " does not exist, no deletion.");
return;
}
//1- p has no child (p is a leaf node)
if(p.left==null && p.right==null) {
if(f==null) // The tree is one node
root=null;
else {
if(f.left==p)
f.left=null;
else
f.right=null;
}
return;
}
//2- p has the left child only
if(p.left!=null && p.right==null) {
if(f==null) // p is a root
root=p.left;
else {
if(f.left==p) // p is a left child
f.left=p.left;
else
f.right=p.left;
}
return;
}
//3- p has the right child only
if(p.left==null && p.right!=null) {
if(f==null) // p is a root
root=p.right;
else {
if(f.left==p) // p is a left child
f.left=p.right;
else
f.right=p.right;
}
return;
}
//4- p has both left and right children
if(p.left!=null && p.right!=null) {
Node rp; // p's key will be replaced by rp's one
f=null;
rp = p.left;
// Find the right most node on the left sub-tree
while(rp.right!=null) {f=rp; rp = rp.right;}
p.info = rp.info;
if(f==null) // rp is just a left son of p
p.left=rp.left;
else
f.right=rp.left;
}
}

void visit(Node p) {
if(p==null) return;
System.out.print(" " + p.info);
}

void preOrder(Node p) {
if(p==null) return;
visit(p);
preOrder(p.left);
preOrder(p.right);
}

void inOrder(Node p) {
if(p==null) return;
inOrder(p.left);
visit(p);
inOrder(p.right);
}

void postOrder(Node p) {
if(p==null) return;
postOrder(p.left);
postOrder(p.right);
visit(p);
}

void addArray(int [] a) {
for(int i=0; i<a.length; i++)
insert(a[i]);
}
}

public class Main {
public static void main(String [] args) {
BSTree t = new BSTree();
System.out.println(" BST after insertion (3 5 1 5 9 8 2):");
int [] a = {3,5,1,5,9,8,2};
t.addArray(a);

/* 3 2
/ \ / \
1 5 1 5
\ \ \
2 9 9
/ /
8 8
- Pre-order : 3 1 2 5 9 8 - Pre-order : 2 1 5 9 8
- In-order : 1 2 3 5 8 9 - In-order : 1 2 5 8 9
- Post-order: 2 1 8 9 5 3 - Post-order: 1 8 9 5 2
*/

System.out.print(" - Pre-order traverse:"); t.preOrder(t.root);
System.out.print("\n - In-order traverse:"); t.inOrder(t.root);
System.out.print("\n - Post-order traverse: "); t.postOrder(t.root);
System.out.print("\n Ater deleting 3:"); t.copyDele(3);
System.out.print("\n - Pre-order traverse:"); t.preOrder(t.root);
System.out.print("\n - In-order traverse:"); t.inOrder(t.root);
System.out.print("\n - Post-order traverse: "); t.postOrder(t.root);
System.out.println();
}
}