boundaryTraversal.cpp

// Implemented by Kritagya Kumra
#include <iostream>
#include <vector>
#include <queue>
using namespace std;
class node
{
public:
    int data;
    node *left;
    node *right;

    node(int d)
    {
        this->data = d;
        this->left = NULL;
        this->right = NULL;
    }
};

void traverseLeft(node *root, vector<int> &ans)
{
    if ((root == NULL) || (root->left == NULL && root->right == NULL))
    {
        return;
    }
    ans.push_back(root->data);
    if (root->left != NULL)
        traverseLeft(root->left, ans);
    else
        traverseLeft(root->right, ans);
}
void traverseLeaf(node *root, vector<int> &ans)
{
    if (root == NULL)
    {
        return;
    }
    if (root->left == NULL && root->right == NULL)
    {
        ans.push_back(root->data);
        return;
    }
    if (root->left != NULL)
        traverseLeaf(root->left, ans);
    if (root->right != NULL)
        traverseLeaf(root->right, ans);
}
void traverseRight(node *root, vector<int> &ans)
{
    if ((root == NULL) || (root->left == NULL && root->right == NULL))
    {
        return;
    }
    if (root->right != NULL)
        traverseRight(root->right, ans);
    else
        traverseRight(root->left, ans);
    ans.push_back(root->data);
}
vector<int> boundaryTraversal(node *root)
{
    vector<int> ans;
    if (root == NULL)
    {
        return ans;
    }
    ans.push_back(root->data);
    traverseLeft(root->left, ans);
    traverseLeaf(root->left, ans);
    traverseLeaf(root->right, ans);
    traverseRight(root->right, ans);
    return ans;
}
int main()
{
    node *root1 = new node(10);
    root1->left = new node(8);
    root1->right = new node(2);
    root1->left->left = new node(3);
    root1->left->right = new node(5);
    root1->right->left = new node(22);
    root1->right->left->right = new node(12);
    root1->right->left->right->left = new node(11);
    // node *root1 = new node(20);
    // root1->left = new node(8);
    // root1->right = new node(12);
    // root1->left->left = new node(3);
    // root1->left->right = new node(5);
    // root1->right->left = new node(2);
    // root1->right->right = new node(10);

    node *root = new node(10);
    root->left = new node(20);
    root->right = new node(30);
    root->left->left = new node(40);
    root->left->right = new node(60);
    // bool ans = isBalanced(root);
    vector<int> ans = boundaryTraversal(root1);
    for (int i = 0; i < ans.size(); i++)
    {
        cout << ans[i] << " ";
    }
}
// Implemented by Kritagya Kumra