binary_tree_right_view.py

binary_tree_right_view.py

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+# ==============================================
+# Project: Binary Tree Right Side View
+# Language: Python 3
+# Description:
+#   Given the root of a binary tree, return the values of the nodes
+#   you can see ordered from top to bottom from the right side.
+# ==============================================
+
+from collections import deque
+from typing import List, Optional
+
+# Definition for a binary tree node
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class BinaryTreeRightView:
+    def rightSideView(self, root: Optional[TreeNode]) -> List[int]:
+        if not root:
+            return []
+
+        view = []
+        queue = deque([root])
+
+        # Level-order traversal (BFS)
+        while queue:
+            level_size = len(queue)
+            for i in range(level_size):
+                node = queue.popleft()
+                if node.left:
+                    queue.append(node.left)
+                if node.right:
+                    queue.append(node.right)
+                # last node of this level → visible from right side
+                if i == level_size - 1:
+                    view.append(node.val)
+        return view
+
+
+if __name__ == "__main__":
+    print("=============================================")
+    print("        BINARY TREE RIGHT SIDE VIEW")
+    print("=============================================")
+
+    # Create binary tree:
+    #        1
+    #      /   \
+    #     2     3
+    #      \     \
+    #       5     4
+    root = TreeNode(1)
+    root.left = TreeNode(2)
+    root.right = TreeNode(3)
+    root.left.right = TreeNode(5)
+    root.right.right = TreeNode(4)
+
+    solver = BinaryTreeRightView()
+    print("Right Side View:", solver.rightSideView(root))
+
+    print("\nProgram completed successfully!")