avin-sharma

class Solution:
    def numDecodings(self, s: str) -> int:
        # 2216 -> 2 2 1 6, 2 21 6, 22 1 6, 2 2 16, 22 16
        # 221 -> 2 2 1, 2 21, 22 1
        # 22 -> 2 2, 22
        
        if s[0] == '0':
            return 0
        decodes = [0 for _ in range(len(s) + 1)]
        decodes[0] = 1

avin-sharma

class Solution:
    def longestValidParentheses(self, s: str) -> int:
        if not s:
            return 0
        
        isValid = [0 for _ in range(len(s))]
        
        for i in range(len(s)):
            if s[i] == ')':
                if i > 0 and s[i-1] == '(':

avin-sharma

class Solution:
    def longestPalindrome(self, s: str) -> str:
        longest = 0
        p = ''
        n = len(s)
        
        for i in range(len(s)):
            length = self.isPalindrome(i, i, s, n)
            if length > longest:
                longest = length

avin-sharma

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def flatten(self, root: TreeNode, right:TreeNode = None) -> None:
        """

avin-sharma

class Solution:
    def subarraySum(self, nums: List[int], k: int) -> int:
        count = 0
        cumulative = {0:1}
        total = 0
        
        for i in range(len(nums)):
            total += nums[i]
            if total - k in cumulative:
                count += cumulative[total - k]

avin-sharma

# Terminal TIC-TAC-TOE
# Written in Python 3

class Board:

    def __init__(self, n=3):
        self.n = n
        self.state = [[' ' for _ in range(n)]  for _ in range(n)]
        self.active_player = 'X'
        self.t = 0

avin-sharma

# https://www.hackerrank.com/challenges/ctci-find-the-running-median/problem

import sys

minHeap = []
maxHeap = []
minSize = 0
maxSize = 0

def getParentIndex(index):

avin-sharma

# https://www.hackerrank.com/challenges/ctci-queue-using-two-stacks

class MyQueue(object):
    def __init__(self):
        self.pushStack = []
        self.popStack = []
    
    def peek(self):
        if not self.popStack:
            while self.pushStack:

avin-sharma

# https://www.hackerrank.com/challenges/ctci-balanced-brackets

def is_matched(expression):
    open_brackets = '{[('
    stack = []
    d = {'}':'{', ')':'(', ']':'['}
    for c in expression:
        if c in open_brackets:
            stack.append(c)
        elif len(stack) == 0:

avin-sharma

# https://www.hackerrank.com/challenges/ctci-linked-list-cycle/problem

"""
Detect a cycle in a linked list. Note that the head pointer may be 'None' if the list is empty.

A Node is defined as: 
 
    class Node(object):
        def __init__(self, data = None, next_node = None):
            self.data = data