matrix.py

# Set Matrix Zeroes
def setZeroes(matrix: List[List[int]]) -> None:
    rows, cols = len(matrix), len(matrix[0])
    zero_rows, zero_cols = set(), set()

    for i in range(rows):
        for j in range(cols):
            if matrix[i][j] == 0:
                zero_rows.add(i)
                zero_cols.add(j)

    for i in range(rows):
        for j in range(cols):
            if i in zero_rows or j in zero_cols:
                matrix[i][j] = 0

# Spiral Matrix
def spiralOrder(matrix: List[List[int]]) -> List[int]:
    res = []
    while matrix:
        res += matrix.pop(0)
        matrix = list(zip(*matrix))[::-1]
    return res

# Rotate Image
def rotate(matrix: List[List[int]]) -> None:
    n = len(matrix)
    for i in range(n // 2):
        for j in range(i, n - i - 1):
            temp = matrix[i][j]
            matrix[i][j] = matrix[n - j - 1][i]
            matrix[n - j - 1][i] = matrix[n - i - 1][n - j - 1]
            matrix[n - i - 1][n - j - 1] = matrix[j][n - i - 1]
            matrix[j][n - i - 1] = temp

# Word Search
def exist(board: List[List[str]], word: str) -> bool:
    def dfs(i, j, k):
        if not (0 <= i < len(board)) or not (0 <= j < len(board[0])) or board[i][j] != word[k]:
            return False
        if k == len(word) - 1:
            return True
        tmp, board[i][j] = board[i][j], '/'
        res = dfs(i + 1, j, k + 1) or dfs(i - 1, j, k + 1) or dfs(i, j + 1, k + 1) or dfs(i, j - 1, k + 1)
        board[i][j] = tmp
        return res

    for i in range(len(board)):
        for j in range(len(board[0])):
            if dfs(i, j, 0):
                return True
    return False