CoursesUniverse

Loading…

CoursesUniverse

Back to practice

EASYTrees & BST

Maximum Depth of Binary Tree

LeetCode

Commonly asked at:Amazon Google LinkedIn

Maximum Depth of Binary Tree

Given a binary tree, return its maximum depth (the number of nodes along the longest path from root to a leaf).

Example

Input (level-order, null for missing): 3 9 20 null null 15 7 Output: 3

Approach

The depth of a tree is 1 (for the root itself) plus the deeper of its two subtrees' depths — a two-line recursive definition. An empty tree has depth 0.

Input format

Line 1: the tree in level-order, space-separated, null for a missing child (this is LeetCode's own tree-input convention)

Print the maximum depth.

Not solved yet

Ctrl+Enter

Editor

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

Input (stdin)

Output

Run your code to see output here.

Isolated sandbox · not executed on your devicePowered by Judge0 CE (free, self-hosted). Runs in an isolated sandbox — not on your device.

Editor

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

Input (stdin)

Output

Run your code to see output here.

Isolated sandbox · not executed on your devicePowered by Judge0 CE (free, self-hosted). Runs in an isolated sandbox — not on your device.

Loading…

Back to practice

EASYTrees & BST

Maximum Depth of Binary Tree

LeetCode

Commonly asked at:Amazon Google LinkedIn

Maximum Depth of Binary Tree

Given a binary tree, return its maximum depth (the number of nodes along the longest path from root to a leaf).

Example

Input (level-order, null for missing): 3 9 20 null null 15 7 Output: 3

Approach

The depth of a tree is 1 (for the root itself) plus the deeper of its two subtrees' depths — a two-line recursive definition. An empty tree has depth 0.

Input format

Line 1: the tree in level-order, space-separated, null for a missing child (this is LeetCode's own tree-input convention)

Print the maximum depth.

Not solved yet

Ctrl+Enter

Editor

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

Input (stdin)

Output

Run your code to see output here.

Isolated sandbox · not executed on your devicePowered by Judge0 CE (free, self-hosted). Runs in an isolated sandbox — not on your device.

Editor

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

# Tree is provided level-order with 'null' markers; build_tree() constructs it for you.
class TreeNode:
    def __init__(self, val=0):
        self.val = val
        self.left = None
        self.right = None

def build_tree(tokens):
    if not tokens or tokens[0] == 'null':
        return None
    root = TreeNode(int(tokens[0]))
    queue = [root]
    i = 1
    while queue and i < len(tokens):
        node = queue.pop(0)
        if i < len(tokens) and tokens[i] != 'null':
            node.left = TreeNode(int(tokens[i])); queue.append(node.left)
        i += 1
        if i < len(tokens) and tokens[i] != 'null':
            node.right = TreeNode(int(tokens[i])); queue.append(node.right)
        i += 1
    return root

tokens = input().split()
root = build_tree(tokens)
# TODO: depth(node) = 0 if node is None else 1 + max(depth(left), depth(right))

Input (stdin)

Output

Run your code to see output here.

Isolated sandbox · not executed on your devicePowered by Judge0 CE (free, self-hosted). Runs in an isolated sandbox — not on your device.

Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

Example

Approach

Input format

Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

Example

Approach

Input format

Community Discussions