Added AVL tree

Author: captainWaheed

Trees/AVL Tree.cpp

@@ -0,0 +1,286 @@
+#include <iostream>
+#include <queue>
+#include <unordered_map>
+using namespace std;
+
+struct node {
+    struct node *left;
+    int data;
+    int height;
+    struct node *right;
+};
+
+class AVL
+{
+private:
+    
+public:
+    struct node * root;
+    AVL(){
+        this->root = NULL;
+
+    }
+
+    int calheight(struct node *p){
+
+            if(p->left && p->right){
+            if (p->left->height < p->right->height)
+                return p->right->height + 1;
+            else return  p->left->height + 1;
+            }
+            else if(p->left && p->right == NULL){
+               return p->left->height + 1;
+            }
+            else if(p->left ==NULL && p->right){
+               return p->right->height + 1;
+            }
+            return 0;
+
+    }
+
+    int bf(struct node *n){
+            if(n->left && n->right){
+                return n->left->height - n->right->height; 
+            }
+            else if(n->left && n->right == NULL){
+                return n->left->height; 
+            }
+            else if(n->left== NULL && n->right ){
+                return -n->right->height;
+            }
+    }
+
+    struct node * llrotation(struct node *n){
+        struct node *p;
+        struct node *tp;
+        p = n;
+        tp = p->left;
+
+        p->left = tp->right;
+        tp->right = p;
+
+        return tp; 
+    }
+
+
+    struct node * rrrotation(struct node *n){
+        struct node *p;
+        struct node *tp;
+        p = n;
+        tp = p->right;
+
+        p->right = tp->left;
+        tp->left = p;
+
+        return tp; 
+    }
+
+
+    struct node * rlrotation(struct node *n){
+        struct node *p;
+        struct node *tp;
+        struct node *tp2;
+        p = n;
+        tp = p->right;
+        tp2 =p->right->left;
+
+        p -> right = tp2->left;
+        tp ->left = tp2->right;
+        tp2 ->left = p;
+        tp2->right = tp; 
+        
+        return tp2; 
+    }
+
+    struct node * lrrotation(struct node *n){
+        struct node *p;
+        struct node *tp;
+        struct node *tp2;
+        p = n;
+        tp = p->left;
+        tp2 =p->left->right;
+
+        p -> left = tp2->right;
+        tp ->right = tp2->left;
+        tp2 ->right = p;
+        tp2->left = tp; 
+        
+        return tp2; 
+    }
+
+    struct node* insert(struct node *r,int data){
+        
+        if(r==NULL){
+            struct node *n;
+            n = new struct node;
+            n->data = data;
+            r = n;
+            r->left = r->right = NULL;
+            r->height = 1; 
+            return r;             
+        }
+        else{
+            if(data < r->data)
+            r->left = insert(r->left,data);
+            else
+            r->right = insert(r->right,data);
+        }
+
+        r->height = calheight(r);
+
+        if(bf(r)==2 && bf(r->left)==1){
+            r = llrotation(r);
+        }
+        else if(bf(r)==-2 && bf(r->right)==-1){
+            r = rrrotation(r);
+        }
+        else if(bf(r)==-2 && bf(r->right)==1){
+            r = rlrotation(r);
+        }
+        else if(bf(r)==2 && bf(r->left)==-1){
+            r = lrrotation(r);
+        }        
+
+        return r;
+
+        }
+
+    void levelorder_newline(){
+        if (this->root == NULL){
+            cout<<"\n"<<"Empty tree"<<"\n";
+            return;            
+        }
+        levelorder_newline(this->root);
+    }
+
+    void levelorder_newline(struct node *v){
+        queue <struct node *> q;
+        struct node *cur;
+        q.push(v);
+        q.push(NULL);      
+
+        while(!q.empty()){
+            cur = q.front();
+            q.pop();
+            if(cur == NULL && q.size()!=0){
+                cout<<"\n";
+                
+                q.push(NULL);
+                continue;
+            }
+            if(cur!=NULL){
+                cout<<" "<<cur->data;
+
+                if (cur->left!=NULL){
+                q.push(cur->left);
+                }
+                if (cur->right!=NULL){
+                    q.push(cur->right);
+                }
+            }
+            
+            
+        }
+    }
+ 
+    struct node * deleteNode(struct node *p,int data){
+
+        if(p->left == NULL && p->right == NULL){
+                if(p==this->root)
+                    this->root = NULL;
+            delete p;
+            return NULL;
+        }
+
+        struct node *t;
+        struct node *q;
+        if(p->data < data){
+            p->right = deleteNode(p->right,data);
+        }
+        else if(p->data > data){
+            p->left = deleteNode(p->left,data);
+        }
+        else{
+            if(p->left != NULL){
+                q = inpre(p->left);
+                p->data = q->data;
+                p->left=deleteNode(p->left,q->data);
+            }
+            else{
+                q = insuc(p->right);
+                p->data = q->data;
+                p->right = deleteNode(p->right,q->data);
+            }
+        }
+
+        if(bf(p)==2 && bf(p->left)==1){ p = llrotation(p); }                  
+        else if(bf(p)==2 && bf(p->left)==-1){ p = lrrotation(p); }
+        else if(bf(p)==2 && bf(p->left)==0){ p = llrotation(p); }
+        else if(bf(p)==-2 && bf(p->right)==-1){ p = rrrotation(p); }
+        else if(bf(p)==-2 && bf(p->right)==1){ p = rlrotation(p); }
+        else if(bf(p)==-2 && bf(p->right)==0){ p = llrotation(p); }
+
+        
+        return p;
+    }
+
+     struct node* inpre(struct node* p){
+        while(p->right!=NULL)
+            p = p->right;
+        return p;    
+    }
+
+    struct node* insuc(struct node* p){
+        while(p->left!=NULL)
+            p = p->left;
+
+        return p;    
+    }
+
+    ~AVL(){
+
+    }
+};
+
+
+int main(){
+
+    AVL b;
+    int c,x;
+
+    do{
+        cout<<"\n1.Display levelorder on newline";
+        cout<<"\n2.Insert";
+        cout<<"\n3.Delete\n";
+        cout<<"\n0.Exit\n";
+        cout<<"\nChoice: ";
+
+        cin>>c;
+
+        switch (c)
+        {
+        case 1:
+            b.levelorder_newline();
+            // to print the tree in level order
+            break;
+                  
+        case 2:
+            cout<<"\nEnter no. ";
+            cin>>x;
+            b.root = b.insert(b.root,x);
+            break;
+        
+        case 3:
+            cout<<"\nWhat to delete? ";
+            cin>>x;
+            b.root = b.deleteNode(b.root,x);
+            break;
+            
+        case 0:
+            break;
+        }
+
+     } while(c!=0);
+  
+}
+