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class Solution:
    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
        
        seen = {}
        
        for s in strs:
            word = ''.join(sorted(s))
            
            if word in seen: 
                seen[word].append(s)

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# no runtime given, but O(n)
class Solution:
    def countElements(self, arr: List[int]) -> int:
        seen = set(arr)
        return sum([1 if n+1 in seen else 0 for n in arr])

# 28ms with reduce; also O(n)
class Solution:
    def countElements(self, arr: List[int]) -> int:
        seen = set(arr)

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# Recurse downwards with helper function, counting the number of nodes as you go
# Go back up the call stack, when you're at the middle, return the node.

class Solution:
    def middleNode(self, head: ListNode) -> ListNode:
        
        def helper(head, count):
            if not head: 
                return count
            rest = helper(head.next, count + 1)

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# stupid 10-minute, O(n) space solution bc andrew was hounding me for trying to go straight for the O(1) space solution
class Solution:
    def backspaceCompare(self, S: str, T: str) -> bool:
        return self.process(S) == self.process(T)

    # return the list of characters that are typed out in the end
    def process(self, s: str) -> list:
        curr_index, string = 0, []
        
        for char in s:

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# 56ms
class MinStack:
    def __init__(self):
        self.minHistory = [float('inf')]
        self.stack = []

    def push(self, x: int) -> None:
        self.stack += [x]
        if x <= self.minHistory[-1]:
            self.minHistory.append(x)

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class Solution:
    def stringShift(self, s: str, shift: List[List[int]]) -> str:
        shifted_amount = sum(i[1] if i[0] else -i[1] for i in shift) % len(s)
        
        if shifted_amount == 0:
            return s
        else:
            return s[-shifted_amount:] + s[:-shifted_amount]
        
# cleaner

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class Solution:
    def leftMostColumnWithOne(self, binaryMatrix: 'BinaryMatrix') -> int:
        num_rows, num_cols = binaryMatrix.dimensions()[0], binaryMatrix.dimensions()[1]
        x, y, last_seen_1 = 0, num_cols-1, "butts"
        
        while x < num_rows and y >= 0:
            if binaryMatrix.get(x, y) == 1:
                last_seen_1 = y
                y -= 1
            elif binaryMatrix.get(x, y) == 0:

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input = open('input/day1.txt', 'r').readlines()
numbers = [int(line) for line in input]

# O(n)
def partOne(numbers=numbers):
    count = 0
    for i in range(1, len(numbers)):
        if numbers[i] > numbers[i-1]:
            count += 1
    return count

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input = open('input/day2.txt', 'r').readlines()
directions = [line for line in input]

# O(n)
def partOne(directions=directions):
    horizontal = 0
    depth = 0

    for step in directions:
        direction, val = step.split(" ", 1)

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input = open('input/day3.txt', 'r').readlines()
strings = [list(line)[:-1] for line in input]

def partOne(strings=strings):
    transposed = [*zip(*strings)]
    gamma_string = ''.join([max(digit, key=digit.count) for digit in transposed])
    epsilon_string = gamma_string.replace('0', 'q').replace('1', '0').replace('q', '1')
    return int(gamma_string, 2)*int(epsilon_string, 2)

def partTwo(strings=strings):