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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4.  
  5. // Node Structure
  6. class Node {
  7. public:
  8.     int data;
  9.     Node* left;
  10.     Node* right;
  11.  
  12.     Node(int x) {
  13.         data = x;
  14.         left = right = nullptr;
  15.     }
  16. };
  17.  
  18. // Recursive function to find left view
  19. void recLeftView(Node* root, int level, vector<int>& result) {
  20.     if (root == nullptr) return;
  21.  
  22.     // first node of current level
  23.     if (level == result.size()) {
  24.         result.push_back(root->data);
  25.     }
  26.  
  27.  
  28.     recLeftView(root->right, level + 1, result);
  29.  
  30.       recLeftView(root->left, level + 1, result);
  31. }
  32.  
  33. // Function which return left view of binary tree
  34. vector<int> leftView(Node* root) {
  35.     vector<int> result;
  36.     recLeftView(root, 0, result);
  37.     return result;
  38. }
  39.  
  40. int main() {
  41.     // Create binary tree
  42.  
  43.     //    1
  44.     //   / \
  45.     //  2   3
  46.     //     /
  47.     //    4
  48.     //     \
  49.     //      5
  50.  
  51.     Node* root = new Node(1);
  52.     root->left = new Node(2);
  53.     root->right = new Node(3);
  54.     root->right->left = new Node(4);
  55.     root->right->left->right = new Node(5);
  56.  
  57.     vector<int> view = leftView(root);
  58.     for (int val : view)
  59.         cout << val << " ";
  60. }
Success #stdin #stdout 0s 5320KB
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1 3 4 5
https://ideone.com/Z0YIVM
language:
C++ (gcc 8.3)
created:
17 hours ago
visibility:
public

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