PAT 1066 Root of AVL Tree

# Include <cstdio> # include <cstdlib> class Node {public: Node * L; Node * R; int height; int data; Node (int val, Node * l = NULL, node * r = NULL, int h = 0): data (val), L (l), R (r), height (h ){}}; inline int height (Node * node) {if (node = NULL) return-1; return node-> height;} inline int max (int a, int B) {return a> B? A: B;}/* K2 is the first node violates the AVL property, k1 is its left node violation is caused by insert a node into the K1's right sub-tree (K2) (K1)/LL-rotate/(K1) --------------> (new) (K2)/(new) */Node * rotateLL (Node * root) {Node * K1 = root-> L; Node * K2 = root; node * kmeanrsub = K1-> R; K1-> R = K2; K2-> L = kmeanrsub; K1-> height = max (height (K1-> L ), height (K1-> R) + 1; K2-> height = max (height (K2-> L), height (K2-> R) + 1; return K1;}/* K1 is the first node violates the AVL property, k2 is its right node violation is caused by insert a node into the K2's left sub-tree (K1) (K2) \ RR-rotate/(K2) --------------> (K1) (new) */Node * rotateRR (Node * root) {Node * K1 = root; Node * K2 = root-> R; node * k2_lsub = K2-> L; K2-> L = K1; K1-> R = k2_lsub; K1-> height = max (height (K1-> L ), height (K 1-> R) + 1; K2-> height = max (height (K2-> L), height (K2-> R) + 1; return K2 ;} /* first do LL rotate on K3, then do RR rotate on K1 (K1) (K1) (K2) \/(K3) ------> (K2) --------> (K1) (K3)/(K2) (K3) */Node * rotateRL (Node * root) {Node * K1 = root; Node * K2 = root-> R-> L; node * K3 = root-> R; K1-> R = rotateLL (K3); return rotateRR (K1);}/* first do RR rotate on K1, then do LL rotate on K3 (K3) (K3) (K2) /// (K1) ------> (K2) ------> (K1) (K3) \/(K2) (K1) */Node * rotateLR (Node * root) {Node * K1 = root-> L; Node * K2 = root-> L-> R; Node * K3 = root; K3-> L = rotateRR (K1 ); return rotateLL (K3);} Node * insert (Node * root, int value) {if (root = NULL) {return new Node (value );} if (value <root-> data) {root-> L = insert (root-> L, value); // do AVL property check if (height (root-> L) -height (root-> R) = 2 ) {If (value <root-> L-> data) {// LL case, single rotation root = rotateLL (root );} else if (value> root-> L-> data) {// LR case, double rotation root = rotateLR (root );}}} else if (value> root-> data) {root-> R = insert (root-> R, value ); // do AVL property check if (height (root-> R)-height (root-> L) = 2) {if (value> root-> R-> data) {// RR case, single rotation root = rotateRR (root);} else If (value <root-> R-> data) {// RL case, double rotation root = rotateRL (root) ;}} else {// equal, do nothing} root-> height = max (height (root-> L), height (root-> R) + 1; return root;} int main () {Node * r = NULL; int N; scanf ("% d", & N); for (int I = 0; I <N; I ++) {int d; scanf ("% d", & d); r = insert (r, d);} if (r! = NULL) {printf ("% d", r-> data);} return 0 ;}

For the first time, write the AVL tree by yourself. Refer to the AVL tree code in Data Structures and Alogrithm Analysis in C version 2.

PAT 1066 Root of AVL Tree