Binary tree path

Author: TonyStark-19

Tree/BinaryTreePaths.cpp

@@ -0,0 +1,91 @@
+#include <iostream>
+#include <vector>
+#include <string>
+using namespace std;
+
+// Node class
+class Node
+{
+public:
+    int data;
+    Node *left;
+    Node *right;
+
+    Node(int val)
+    {
+        data = val;
+        left = right = NULL;
+    }
+};
+
+static int idx = -1;
+Node *buildTree(vector<int> preorder)
+{
+    idx++;
+
+    // base case
+    if (preorder[idx] == -1)
+    {
+        return NULL;
+    }
+
+    // create root node
+    Node *root = new Node(preorder[idx]);
+
+    // left sub tree recursion call
+    root->left = buildTree(preorder);
+
+    // right sub tree recursion call
+    root->right = buildTree(preorder);
+
+    return root;
+}
+
+void allPaths(Node *root, string path, vector<string> &ans)
+{
+    // if root is not there
+    if (!root)
+        return;
+
+    // if it is a leaf node
+    if (root->left == NULL && root->right == NULL)
+    {
+        ans.push_back(path);
+        return;
+    }
+
+    if (root->left)
+    {
+        allPaths(root->left, path + "->" + to_string(root->left->data), ans);
+    }
+
+    if (root->right)
+    {
+        allPaths(root->right, path + "->" + to_string(root->right->data), ans);
+    }
+}
+
+vector<string> binaryTreePaths(Node *root)
+{
+    vector<string> ans;
+    string path = to_string(root->data);
+
+    allPaths(root, path, ans);
+    return ans;
+}
+
+int main()
+{
+    vector<int> preorder = {1, 2, -1, -1, 3, 4, -1, -1, -1};
+    Node *root = buildTree(preorder);
+
+    vector<string> paths = binaryTreePaths(root);
+
+    cout << "Root-to-leaf paths:\n";
+    for (const string &p : paths)
+    {
+        cout << p << endl;
+    }
+
+    return 0;
+}