Clockwise Spiral Traversal of Binary Tree - GeeksforGeeks

14 Feb, 2022
Given a Binary Tree. The task is to print the circular clockwise spiral order traversal of the given binary tree.  
For the above binary tree, the circular clockwise spiral order traversal will be 1, 4, 5, 6, 7, 2, 3. 
Examples:  
Input : 
                       10
                     /     \
                   12       13
                          /     \
                       14       15
                      /   \     /  \
                     21   22   23   24
Output : 10, 24, 23, 22, 21, 12, 13, 15, 14
 
Approach:  
First calculate the width of the given tree.Create an auxiliary 2D array of order (width*width)Do level order traversal of the binary tree and store levels in the newly created 2D matrix one by one in respective rows. That is, store nodes at level 0 at row indexed 0, nodes at level 1 at row indexed 1 and so on.Finally, traverse the 2d array in the below fashion: Start from the first row from left to right and print elements.Then traverse the last row from right to left and print elements.Again traverse the second row from left to right and print.Then second last row from right to left and so on and repeat the steps until the complete 2-D array is traversed.
First calculate the width of the given tree.
Create an auxiliary 2D array of order (width*width)
Do level order traversal of the binary tree and store levels in the newly created 2D matrix one by one in respective rows. That is, store nodes at level 0 at row indexed 0, nodes at level 1 at row indexed 1 and so on.
Finally, traverse the 2d array in the below fashion: Start from the first row from left to right and print elements.Then traverse the last row from right to left and print elements.Again traverse the second row from left to right and print.Then second last row from right to left and so on and repeat the steps until the complete 2-D array is traversed.
Start from the first row from left to right and print elements.
Then traverse the last row from right to left and print elements.
Again traverse the second row from left to right and print.
Then second last row from right to left and so on and repeat the steps until the complete 2-D array is traversed.
Below is the implementation of the above approach:  
C++
Python3
// C++ program for Clockwise Spiral Traversal// of Binary Tree #include <bits/stdc++.h>using namespace std; // A Tree nodestruct Node {    int key;    struct Node *left, *right;}; // Utility function to create a new nodeNode* newNode(int key){    Node* temp = new Node;    temp->key = key;    temp->left = temp->right = NULL;    return (temp);}//function to calculate the height of the treeint findHeight(struct Node* node){    //Base condition    if(node == NULL) return 0;    int leftHeight = findHeight(node->left);    int rightHeight = findHeight(node->right);    //return maximum of left or right subtree height addition with one    return 1+(leftHeight > rightHeight ? leftHeight : rightHeight );}// Function to find the width of treevoid findWidth(struct Node* node, int& maxValue,            int& minValue, int hd){    if (node == NULL)        return;     if (hd > maxValue) {        maxValue = hd;    }     if (hd < minValue) {        minValue = hd;    }     findWidth(node->left, maxValue, minValue, hd - 1);    findWidth(node->right, maxValue, minValue, hd + 1);} // Function to traverse the tree and// store level order traversal in a matrixvoid BFS(int** mtrx, struct Node* node){    // Create queue for storing    // the addresses of nodes    queue<struct Node*> qu;     qu.push(node);     int i = -1, j = -1;     struct Node* poped_node = NULL;     while (!qu.empty()) {         i++;         int qsize = qu.size();         while (qsize--) {            j++;             poped_node = qu.front();             // Store data of node into the matrix            mtrx[i][j] = poped_node->key;            qu.pop();             if (poped_node->left != NULL) {                qu.push(poped_node->left);            }             if (poped_node->right != NULL) {                qu.push(poped_node->right);            }        }         j = -1;    }} // Function for Clockwise Spiral Traversal// of Binary Treevoid traverse_matrix(int** mtrx, int height, int width){    int j = 0, k1 = 0, k2 = 0, k3 = height - 1;    int k4 = width - 1;     for (int round = 0; round < height / 2; round++) {        for (j = k2; j < width; j++) {             // only print those values which            // are not MAX_INTEGER            if (mtrx[k1][j] != INT_MAX) {                cout << mtrx[k1][j] << ", ";            }        }         k2 = 0;        k1++;         for (j = k4; j >= 0; j--) {             // only print those values which are            // not MAX_INTEGER            if (mtrx[k3][j] != INT_MAX) {                cout << mtrx[k3][j] << ", ";            }        }         k4 = width - 1;        k3--;    }     // condition (one row may be left traversing)    // if number of rows in matrix are odd    if (height % 2 != 0) {        for (j = k2; j < width; j++) {             // only print those values which are            // not MAX_INTEGER            if (mtrx[k1][j] != INT_MAX) {                cout << mtrx[k1][j] << ", ";            }        }    }} // A utility function to print clockwise// spiral traversal of treevoid printPattern(struct Node* node){    // max, min has taken for    // calculating width of tree    int max_value = INT_MIN;    int min_value = INT_MAX;    int hd = 0;     // calculate the width of a tree    findWidth(node, max_value, min_value, hd);    int width = max_value + abs(min_value);        //calculate the height of the tree    int height = findHeight(node);        // use double pointer to create 2D array    int** mtrx = new int*[height];     // initialize width for each row of matrix    for (int i = 0; i < height; i++) {        mtrx[i] = new int[width];    }     // initialize complete matrix with    // MAX INTEGER(purpose garbage)    for (int i = 0; i < height; i++) {        for (int j = 0; j < width; j++) {            mtrx[i][j] = INT_MAX;        }    }     // Store the BFS traversal of the tree    // into the 2-D matrix    BFS(mtrx, node);     // Print the circular clockwise spiral    // traversal of the tree    traverse_matrix(mtrx, height, width);     // release extra memory    // allocated for matrix    free(mtrx);} // Driver Codeint main(){    /*     10        /     \    12     13        /     \        14     15        / \     / \        21 22 23 24             Let us create Binary Tree as shown    in above example */     Node* root = newNode(10);    root->left = newNode(12);    root->right = newNode(13);       root->right->left = newNode(14);    root->right->right = newNode(15);       root->right->left->left = newNode(21);    root->right->left->right = newNode(22);    root->right->right->left = newNode(23);    root->right->right->right = newNode(24);     cout << "Circular Clockwise Spiral Traversal : \n";     printPattern(root);     return 0;}// This code is contributed by MOHAMMAD MUDASSIR
# Python3 program for Clockwise Spiral# Traversal of Binary TreeINT_MAX = 2**31INT_MIN = -2**31 # Binary tree nodeclass newNode:     # Constructor to create a newNode    def __init__(self, data):        self.key = data        self.left = None        self.right = None         # Function to find the width of treedef findWidth(node, maxValue, minValue, hd):     if (node == None):        return     if (hd > maxValue[0]):        maxValue[0] = hd         if (hd < minValue[0]):        minValue[0] = hd     findWidth(node.left, maxValue,                         minValue, hd - 1)    findWidth(node.right, maxValue,                          minValue, hd + 1) # Function to traverse the tree and# store level order traversal in a matrixdef BFS(mtrx,node):     # Create queue for storing    # the addresses of nodes    qu = []     qu.append(node)     i = -1    j = -1     poped_node = None     while (len(qu)):        i += 1         qsize = len(qu)         while (qsize > 0):            qsize -= 1            j += 1             poped_node = qu[0]             # Store data of node into the matrix            mtrx[i][j] = poped_node.key            qu.pop(0)             if (poped_node.left != None):                qu.append(poped_node.left)                         if (poped_node.right != None):                qu.append(poped_node.right)                     j = -1     # Function for Clockwise Spiral# Traversal of Binary Treedef traverse_matrix(mtrx, width):     j = 0    k1 = 0    k2 = 0    k3 = width - 1    k4 = width - 1     for round in range(width // 2):        for j in range(k2, width):             # only print those values which            # are not MAX_INTEGER            if (mtrx[k1][j] != INT_MAX):                print(mtrx[k1][j], ", ", end = "")        k2 = 0        k1 += 1         for j in range(k4, -1, -1):             # only print those values which are            # not MAX_INTEGER            if (mtrx[k3][j] != INT_MAX):                print(mtrx[k3][j], ", ", end = "")                 k4 = width - 1        k3 -= 1     # condition (one row may be left traversing)    # if number of rows in matrix are odd    if (width % 2 != 0):        for j in ramge(k2, width):             # only print those values which            # are not MAX_INTEGER            if (mtrx[k1][j] != INT_MAX):                print(mtrx[k1][j], ", ", end = "")                 # A utility function to prclockwise# spiral traversal of treedef printPattern(node):     # max, min has taken for    # calculating width of tree    max_value = [INT_MIN]    min_value = [INT_MAX ]    hd = 0     # calculate the width of a tree    findWidth(node, max_value, min_value, hd)    width = max_value[0] + abs(min_value[0])     # use double pointer to    # create 2D array    mtrx = [0]*width     # initialize width for each    # row of matrix    for i in range(width):        mtrx[i] = [0] * width         # initialize complete matrix with    # MAX INTEGER(purpose garbage)    for i in range(width):        for j in range(width):            mtrx[i][j] = INT_MAX             # Store the BFS traversal of the    # tree into the 2-D matrix    BFS(mtrx, node)         # Print the circular clockwise spiral    # traversal of the tree    traverse_matrix(mtrx, width)         # Driver Codeif __name__ == '__main__':         """     10        /     \    12     13        /     \        14     15        / \     / \        21 22 23 24             Let us create Binary Tree as shown    in above example """     root = newNode(10)    root.left = newNode(12)    root.right = newNode(13)     root.right.left = newNode(14)    root.right.right = newNode(15)     root.right.left.left = newNode(21)    root.right.left.right = newNode(22)    root.right.right.left = newNode(23)    root.right.right.right = newNode(24)     print("Circular Clockwise Spiral Traversal :")     printPattern(root) # This code is contributed by# SHUBHAMSINGH10
Circular Clockwise Spiral Traversal : 
10, 24, 23, 22, 21, 12, 13, 15, 14,
 
SHUBHAMSINGH10
MohammadMudassir
nidhi_biet
simmytarika5
Binary Tree
C++ Programs
Tree
Tree
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
cin in C++
CSV file management using C++
Shallow Copy and Deep Copy in C++
Check if given number is perfect square
Passing a function as a parameter in C++
Tree Traversals (Inorder, Preorder and Postorder)
Binary Tree | Set 1 (Introduction)
Level Order Binary Tree Traversal
AVL Tree | Set 1 (Insertion)
Inorder Tree Traversal without Recursion