tree traversals and views, iterative and recursive traversal of in,pr…

Trees algorithm/avl_tree_rotations_insert_deletion.cpp

@@ -0,0 +1,176 @@
+// Manav Dhiman
+#include<bits/stdc++.h>
+using namespace std;
+#define endl "\n"
+#define loop(i,n) for(i=0;i<n;i++)
+#define loop1(i,k,n) for(i=k;i<n;i++)
+#define pb push_back
+typedef long long int ll;
+struct node{
+    int data;
+    node* left;
+    node* right;
+    int ht;
+    node(int x){
+        data=x;
+        left=right=NULL;
+        ht=1;
+    }
+};
+void inorder(node* root){
+    if(root==NULL) return;
+    inorder(root->left);
+    cout<<root->data<<" ";
+    inorder(root->right);
+    return;
+}
+void preorder(node* root){
+    if(root==NULL) return;
+    cout<<root->data<<" ";
+    preorder(root->left);
+    preorder(root->right);
+    return;
+}
+int height(node* root){
+    if(root==NULL) return 0;
+    return max(height(root->left),height(root->right))+1;
+}
+int balancefactor(node* root){
+    if(root==NULL) return 0;
+    int hl=root->left?root->left->ht:0;
+    int hr=root->right?root->right->ht:0;
+    return hl-hr; 
+}
+node* LLrotation(node* root){
+    node* p=root->left;
+    node* temp=p->right;
+    p->right=root;
+    root->left=temp;
+    root->ht=height(root);
+    p->ht=height(p);
+    return p;
+}
+node* LRrotation(node* root){
+    node *temp=(root)->left;
+    node* temp2=temp->right;
+    temp->right=temp2->left;
+    (root)->left=temp2->right;
+    temp2->left=temp;
+    temp2->right=root;
+    temp2->ht=height(temp2);
+    temp->ht=height(temp);
+    (root)->ht=height(root);
+    return temp2;
+}
+node* RRrotation(node* root){
+    node* temp=(root)->right;
+    node* temp2=temp->left;
+    temp->left=root;
+    (root)->right=temp2;
+    temp->ht=height(temp);
+    (root)->ht=height(root);
+    return temp;
+}
+node* RLrotation(node* root){
+    node* temp=(root)->right;
+    node* temp2=temp->left;
+    (root)->right=temp2->left;
+    temp->left=temp2->right;
+    temp2->left=root;
+    temp2->right=temp;
+    temp->ht=height(temp);
+    temp2->ht=height(temp2);
+    (root)->ht=height(root);
+    return temp2;
+}
+node* insert(node* root,int x){
+    node* temp=new node(x);
+    if(root==NULL){
+        root=temp;
+        return root;
+    }
+    else if((root)->data>x) root->left=insert(((root)->left),x);
+    else root->right=insert(((root)->right),x);
+    (root)->ht=height(root);
+    if(balancefactor(root)>1&&x<(root)->left->data){
+        return LLrotation((root));
+    }
+    else if(balancefactor(root)>1&&x>(root)->left->data){
+        return LRrotation(root);
+    }
+    else if(balancefactor(root)<-1&&x>(root)->right->data){
+        return RRrotation((root));
+    }
+    else if(balancefactor(root)<-1&&x<(root)->right->data){
+        return RLrotation((root));
+    }
+    return root;
+}
+node* minval(node* root){
+    node* curr=root;
+    if(root==NULL) return NULL;
+    while(curr&&curr->left!=NULL) curr=curr->left;
+    return curr;
+}
+node* avldel(node* root,int x){
+    if(root==NULL) return root;
+    else if((root)->data>x) root->left=avldel(root->left,x);
+    else if(root->data<x) root->right=avldel(root->right,x);
+    else{
+        if(root->right==NULL&&(root)->left==NULL){
+            node* temp=root;
+            delete temp;
+            root==NULL;
+        }
+        else if((root)->left==NULL){
+            node* t=(root);
+            (root)=(root)->right;
+            delete t;
+        }
+        else if((root)->right==NULL){
+            node* t=(root);
+            (root)=(root)->left;
+            delete t;
+        }
+        else{
+            node* t=minval(root->right);
+            (root)->data=t->data;
+            root->right=avldel(root->right,t->data);
+        }
+    }
+    if(root==NULL) return root;
+    root->ht=height(root);
+    int bal=balancefactor(root);
+    if(bal>1 && balancefactor(root->left)>=0){
+        return LLrotation((root));
+    }
+    else if(bal>1 && balancefactor(root->left)<0){
+        return LRrotation((root));
+    }
+    else if(bal<-1 && balancefactor(root->right)<=0){
+        return RRrotation((root));
+    }
+    else if(bal<-1 && balancefactor(root->right)>0){
+        return RLrotation((root));
+    }
+    return root;
+}
+int main(){
+    // ios_base::sync_with_stdio(false);
+	// cin.tie(NULL);
+    node* root=NULL;
+    root = insert(root, 9);  
+    root = insert(root, 5);  
+    root = insert(root, 10);  
+    root = insert(root, 0);  
+    root = insert(root, 6);  
+    root = insert(root, 11);  
+    root = insert(root, -1);  
+    root = insert(root, 1);  
+    root = insert(root, 2); 
+    preorder(root);
+    root=avldel(root,10);
+    cout<<endl;
+    preorder(root);
+    return 0;
+}