Print Path from Root to Given Node in Binary Tree using C++

In this tutorial, we will be discussing a program to print the path from root to a given node in a binary tree.

For a given binary tree having distinct nodes, we have to print the complete path to reach a particularly given node from the root node of the binary tree.

To solve this problem, we will use recursion. While traversing the binary tree, we will recursively search for the particular element to be found. Also alongside we will be storing the path to reach the element to be searched.

Example

#include <bits/stdc++.h>
using namespace std;
struct Node{
   int data;
   Node *left, *right;
};
struct Node* create_node(int data){
   struct Node *new_node = new Node;
   new_node->data = data;
   new_node->left = new_node->right = NULL;
   return new_node;
}
//checks if a path from root node to element exists
bool is_path(Node *root, vector<int>& arr, int x){
   if (!root)
      return false;
   arr.push_back(root->data);
   if (root->data == x)
      return true;
   if (is_path(root->left, arr, x) || is_path(root->right, arr, x))
      return true;
   arr.pop_back();
   return false;
}
//printing the path from the root node to the element
void print_path(Node *root, int x){
   vector<int> arr;
   if (is_path(root, arr, x)){
      for (int i=0; i<arr.size()-1; i++)
         cout << arr[i] << " -> ";
         cout << arr[arr.size() - 1];
   }
   else
      cout << "Path doesn't exists" << endl;
}
int main(){
   struct Node *root = create_node(13);
   root->left = create_node(21);
   root->right = create_node(43);
   root->left->left = create_node(34);
   root->left->right = create_node(55);
   root->right->left = create_node(68);
   root->right->right = create_node(79);
   int x = 68;
   print_path(root, x);
   return 0;
}

Output

13 -> 43 -> 68