- data_structure_python·Last edited by bouteille on Apr 3, 2022Linked with GitHubContributed by
There is no commentSelect some text and then click Comment, or simply add a comment to this page from below to start a discussion.Sum Root to Leaf Numbers
https://leetcode.com/problems/sum-root-to-leaf-numbers/
# 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 Solution:
def sumNumbers(self, root: Optional[TreeNode]) -> int:
def dfs(node, path):
path += str(node.val)
if node.left: dfs(node.left, path)
if node.right: dfs(node.right, path)
if node.left == None and node.right == None:
root_to_leaf_paths.append(path)
root_to_leaf_paths = []
dfs(root, "")
return sum([int(elt) for elt in root_to_leaf_paths])
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Find K Closest Elements
https://leetcode.com/problems/find-k-closest-elements/ Naive def findClosestElements(self, arr: List[int], k: int, x: int) -> List[int]: L = sorted([(abs(elt - x), elt) for elt in arr], key=lambda tup: tup[0]) return sorted([tup[1] for tup in L[:k]]) Opti
Sep 23, 2022Min Stack <img src="https://img.shields.io/badge/-easy-brightgreen">
Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Removes the element on top of the stack. top() -- Get the top element. getMin() -- Retrieve the minimum element in the stack. Example: MinStack minStack = new MinStack();
Jun 27, 2022Valid Parentheses <img src="https://img.shields.io/badge/-easy-brightgreen">
Given a string containing just the characters $($, $)$, ${$, $}$, $[$ and $]$, determine if the input string is valid. An input string is valid if: 1. Open brackets must be closed by the same type of brackets. 2. Open brackets must be closed in the correct order. Note that an empty string is also considered valid. Example 1:
Jun 27, 20223sum
Solution 1 Time complexity: O(n³) Space complexity: O(n) class Solution: def threeSum(self, nums: List[int]) -> List[List[int]]: n = len(nums) if n < 3: return []
Apr 23, 2022
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