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  1. Prepare
  2. Data Structures
  3. Trees
  4. Tree : Top View
  5. Discussions

Tree : Top View

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944 Discussions

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  • williammabotjae1
     + 0 comments

    1 case failed, can you spot the bug?

    Create the top_view method

    def top_view(root: BinaryTreeNode) -> None: if root is None: return 

    # Dictionary to store the first node at each horizontal distance
top_view_map = {}

# List for level order traversal (acting as a queue)
queue = [(root, 0)]  # (node, horizontal distance)

while queue:
    # Pop the first element from the list
    node, hd = queue[0]  # Get the first element
    queue = queue[1:]    # Remove the first element

    # If this is the first time we are visiting this horizontal distance
    if hd not in top_view_map:
        top_view_map[hd] = node.value

    # Add left and right children to the queue with updated horizontal distances
    if node.left:
        queue.append((node.left, hd - 1))
    if node.right:
        queue.append((node.right, hd + 1))

# Sort the horizontal distances and print the corresponding node values
for hd in sorted(top_view_map.keys()):
    print(top_view_map[hd], end=" ")

  • tmack0
     + 0 comments

    The problem definition is unclear in defining "top" view. "Visible" from top nodes?? The example given makes it seem a simple right-only traversal will always work.

  • sufian2878
     + 0 comments

    Can you help me a data structure for my [apk](https://snapwithapk.net/) site.i want to for my Wordpress website.

  • ferociousalapaca
     + 0 comments
    # Creates a nested dictionary indexed by level and
# radius as coordinates pointing to each node.info
def tree_Coords(root, d, radius, level):
    if not root:
        return
    if level not in d.keys():
        d[level] = dict()
    d[level].update({radius: root.info})
    tree_Coords(root.left, d, radius-1, level+1)
    tree_Coords(root.right, d, radius+1, level+1)

def topView(root):
    radius = 0
    level = 0
    if not root:
        return
    d = dict()
    tree_Coords(root, d, radius, level)
    res = dict()
    
    # Nested loop scans and adds values to res when no value exists for
    # a specific radius. If raidus index already exists in res, then there existed
    # another value with the same radius on a previous level(above).
    for level in d.keys():
        for radius in d[level].keys():
            if radius not in res.keys():
                res[radius] = d[level][radius]

    for r in sorted(res.keys()):
        print(res[r], end=" ")

  • pvolpe
     + 0 comments
    from collections import deque
    

def topView(root):
    
    result = {}
    
    bfs = deque()
    bfs.append((root, 0))
    
    while bfs:
        node, distance = bfs.popleft()
        
        if distance not in result:
            result[distance] = node.info
            
        if node.left:
            bfs.append((node.left, distance - 1))
        
        if node.right:
            bfs.append((node.right, distance + 1))
        
    result = dict(sorted(result.items()))
    print(" ".join(map(str, result.values())))