binary_tree_path.py

from pathlib import Path
import sys

sys.path.append(str(Path(__file__).resolve().parent.parent))

from binary_tree import create_binary_tree


class Solution:
    def binaryTreePaths(self, root):
        if root is None:
            return []

        result = []

        def backtrack(node, solution):
            if node is None:
                return

            solution.append(str(node.val))

            if not node.left and not node.right:
                result.append("->".join(solution))

            backtrack(node.left, solution)
            backtrack(node.right, solution)
            solution.pop()

        backtrack(root, [])
        return result


if __name__ == "__main__":

    root = [1, 2, 3, None, 5]
    bt = create_binary_tree(root)

    solution = Solution()

    result = solution.binaryTreePaths(bt)
    assert result == ["1->2->5", "1->3"]
    print(result)
    print("Test Case 1 Passed!")