Homework03

.github/workflows/cs102.yml

@@ -7,10 +7,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.8.6
+    - name: Set up Python 3.9
       uses: actions/setup-python@v2
       with:
-        python-version: '3.8.6'
+        python-version: '3.9'
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip

homework00/hello.py

@@ -1,5 +1,5 @@
 def get_greeting(name: str) -> str:
-    pass
+    return f"Hello, {name}!"
 
 
 if __name__ == "__main__":

homework01/caesar.py

@@ -15,7 +15,16 @@ def encrypt_caesar(plaintext: str, shift: int = 3) -> str:
     ''
     """
     ciphertext = ""
-    # PUT YOUR CODE HERE
+    for i in plaintext:
+        if i.isalpha():
+            if i.isupper():
+                code_i = ord(i) - ord("A")
+                ciphertext += chr((code_i + shift) % 26 + ord("A"))
+            else:
+                code_i = ord(i) - ord("a")
+                ciphertext += chr((code_i + shift) % 26 + ord("a"))
+        else:
+            ciphertext += i
     return ciphertext
 
 
@@ -32,8 +41,19 @@ def decrypt_caesar(ciphertext: str, shift: int = 3) -> str:
     >>> decrypt_caesar("")
     ''
     """
+    # abcdefghijklmnopqrstuvwxyz
+    # zyxwvutsrqponmlkjihgfedcba
     plaintext = ""
-    # PUT YOUR CODE HERE
+    for i in ciphertext:
+        if i.isalpha():
+            if i.isupper():
+                code_i = 25 - ord(i) + ord("A")
+                plaintext += chr(25 - (code_i + shift) % 26 + ord("A"))
+            else:
+                code_i = 25 - ord(i) + ord("a")
+                plaintext += chr(25 - (code_i + shift) % 26 + ord("a"))
+        else:
+            plaintext += i
     return plaintext
 
 

homework01/rsa.py

@@ -1,3 +1,4 @@
+import math
 import random
 import typing as tp
 
@@ -13,8 +14,12 @@ def is_prime(n: int) -> bool:
     >>> is_prime(8)
     False
     """
-    # PUT YOUR CODE HERE
-    pass
+    if n == 1:
+        return False
+    for i in range(2, int(math.sqrt(n)) + 1):
+        if n % i == 0:
+            return False
+    return True
 
 
 def gcd(a: int, b: int) -> int:
@@ -26,8 +31,12 @@ def gcd(a: int, b: int) -> int:
     >>> gcd(3, 7)
     1
     """
-    # PUT YOUR CODE HERE
-    pass
+    while a > 0 and b > 0:
+        if a > b:
+            a %= b
+        else:
+            b %= a
+    return a + b
 
 
 def multiplicative_inverse(e: int, phi: int) -> int:
@@ -38,8 +47,19 @@ def multiplicative_inverse(e: int, phi: int) -> int:
     >>> multiplicative_inverse(7, 40)
     23
     """
-    # PUT YOUR CODE HERE
-    pass
+
+    def loc_0(e, phi):
+        if phi == 0:
+            return 1, 0
+        (q, r) = (e // phi, e % phi)
+        print((q, r))
+        (s, t) = loc_0(phi, r)
+        return t, s - (q * t)
+
+    inverse = loc_0(e, phi)[0]
+    if inverse < 0:
+        inverse += phi
+    return inverse
 
 
 def generate_keypair(p: int, q: int) -> tp.Tuple[tp.Tuple[int, int], tp.Tuple[int, int]]:
@@ -49,10 +69,10 @@ def generate_keypair(p: int, q: int) -> tp.Tuple[tp.Tuple[int, int], tp.Tuple[in
         raise ValueError("p and q cannot be equal")
 
     # n = pq
-    # PUT YOUR CODE HERE
+    n = p * q
 
     # phi = (p-1)(q-1)
-    # PUT YOUR CODE HERE
+    phi = (p - 1) * (q - 1)
 
     # Choose an integer e such that e and phi(n) are coprime
     e = random.randrange(1, phi)
@@ -68,7 +88,7 @@ def generate_keypair(p: int, q: int) -> tp.Tuple[tp.Tuple[int, int], tp.Tuple[in
 
     # Return public and private keypair
     # Public key is (e, n) and private key is (d, n)
-    return ((e, n), (d, n))
+    return (e, n), (d, n)
 
 
 def encrypt(pk: tp.Tuple[int, int], plaintext: str) -> tp.List[int]:
@@ -85,7 +105,7 @@ def decrypt(pk: tp.Tuple[int, int], ciphertext: tp.List[int]) -> str:
     # Unpack the key into its components
     key, n = pk
     # Generate the plaintext based on the ciphertext and key using a^b mod m
-    plain = [chr((char ** key) % n) for char in ciphertext]
+    plain = [chr((char**key) % n) for char in ciphertext]
     # Return the array of bytes as a string
     return "".join(plain)
 

homework01/vigenere.py

@@ -10,7 +10,19 @@ def encrypt_vigenere(plaintext: str, keyword: str) -> str:
     'LXFOPVEFRNHR'
     """
     ciphertext = ""
-    # PUT YOUR CODE HERE
+    for i in range(len(plaintext)):
+        symbol = plaintext[i]
+        if symbol.isalpha():
+            if symbol.isupper():
+                shift = ord(keyword[i % len(keyword)]) - ord("A")
+                code_of_symbol = ord(symbol) - ord("A")
+                ciphertext += chr((code_of_symbol + shift) % 26 + ord("A"))
+            else:
+                shift = ord(keyword[i % len(keyword)]) - ord("a")
+                code_of_symbol = ord(symbol) - ord("a")
+                ciphertext += chr((code_of_symbol + shift) % 26 + ord("a"))
+        else:
+            ciphertext += symbol
     return ciphertext
 
 
@@ -26,5 +38,17 @@ def decrypt_vigenere(ciphertext: str, keyword: str) -> str:
     'ATTACKATDAWN'
     """
     plaintext = ""
-    # PUT YOUR CODE HERE
+    for i in range(len(ciphertext)):
+        symbol = ciphertext[i]
+        if symbol.isalpha():
+            if symbol.isupper():
+                shift = ord(keyword[i % len(keyword)]) - ord("A")
+                code_of_symbol = 25 - ord(symbol) + ord("A")
+                plaintext += chr(25 - (code_of_symbol + shift) % 26 + ord("A"))
+            else:
+                shift = ord(keyword[i % len(keyword)]) - ord("a")
+                code_of_symbol = 25 - ord(symbol) + ord("a")
+                plaintext += chr(25 - (code_of_symbol + shift) % 26 + ord("a"))
+        else:
+            plaintext += symbol
     return plaintext

homework02/sudoku.py

@@ -1,11 +1,12 @@
 import pathlib
+import random
 import typing as tp
 
 T = tp.TypeVar("T")
 
 
 def read_sudoku(path: tp.Union[str, pathlib.Path]) -> tp.List[tp.List[str]]:
-    """ Прочитать Судоку из указанного файла """
+    """Прочитать Судоку из указанного файла"""
     path = pathlib.Path(path)
     with path.open() as f:
         puzzle = f.read()
@@ -19,7 +20,7 @@ def create_grid(puzzle: str) -> tp.List[tp.List[str]]:
 
 
 def display(grid: tp.List[tp.List[str]]) -> None:
-    """Вывод Судоку """
+    """Вывод Судоку"""
     width = 2
     line = "+".join(["-" * (width * 3)] * 3)
     for row in range(9):
@@ -42,7 +43,12 @@ def group(values: tp.List[T], n: int) -> tp.List[tp.List[T]]:
     >>> group([1,2,3,4,5,6,7,8,9], 3)
     [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
     """
-    pass
+    matrix = []
+    i = 0
+    for j in range(n, len(values) + 1, n):
+        matrix.append(values[i:j])
+        i = j
+    return matrix
 
 
 def get_row(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[str]:
@@ -55,7 +61,7 @@ def get_row(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[str
     >>> get_row([['1', '2', '3'], ['4', '5', '6'], ['.', '8', '9']], (2, 0))
     ['.', '8', '9']
     """
-    pass
+    return grid[pos[0]]
 
 
 def get_col(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[str]:
@@ -68,7 +74,10 @@ def get_col(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[str
     >>> get_col([['1', '2', '3'], ['4', '5', '6'], ['.', '8', '9']], (0, 2))
     ['3', '6', '9']
     """
-    pass
+    column = []
+    for i in range(len(grid)):
+        column.append(grid[i][pos[1]])
+    return column
 
 
 def get_block(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[str]:
@@ -82,10 +91,16 @@ def get_block(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.List[s
     >>> get_block(grid, (8, 8))
     ['2', '8', '.', '.', '.', '5', '.', '7', '9']
     """
-    pass
+    block = []
+    number_of_string = pos[0] // 3
+    number_of_column = pos[1] // 3
+    for i in range(number_of_string * 3, number_of_string * 3 + 3):
+        for j in range(number_of_column * 3, number_of_column * 3 + 3):
+            block.append(grid[i][j])
+    return block
 
 
-def find_empty_positions(grid: tp.List[tp.List[str]]) -> tp.Optional[tp.Tuple[int, int]]:
+def find_empty_positions(grid: tp.List[tp.List[str]]):
     """Найти первую свободную позицию в пазле
 
     >>> find_empty_positions([['1', '2', '.'], ['4', '5', '6'], ['7', '8', '9']])
@@ -95,7 +110,14 @@ def find_empty_positions(grid: tp.List[tp.List[str]]) -> tp.Optional[tp.Tuple[in
     >>> find_empty_positions([['1', '2', '3'], ['4', '5', '6'], ['.', '8', '9']])
     (2, 0)
     """
-    pass
+    x = -1
+    for i in grid:
+        y = -1
+        x += 1
+        for j in i:
+            y += 1
+            if j == ".":
+                return x, y
 
 
 def find_possible_values(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -> tp.Set[str]:
@@ -109,11 +131,18 @@ def find_possible_values(grid: tp.List[tp.List[str]], pos: tp.Tuple[int, int]) -
     >>> values == {'2', '5', '9'}
     True
     """
-    pass
-
-
-def solve(grid: tp.List[tp.List[str]]) -> tp.Optional[tp.List[tp.List[str]]]:
-    """ Решение пазла, заданного в grid """
+    numbers = set("123456789")
+    string = set(get_row(grid, pos))
+    column = set(get_col(grid, pos))
+    block = set(get_block(grid, pos))
+    numbers -= string
+    numbers -= column
+    numbers -= block
+    return numbers
+
+
+def solve(grid: tp.List[tp.List[str]]):
+    """Решение пазла, заданного в grid"""
     """ Как решать Судоку?
         1. Найти свободную позицию
         2. Найти все возможные значения, которые могут находиться на этой позиции
@@ -125,13 +154,33 @@ def solve(grid: tp.List[tp.List[str]]) -> tp.Optional[tp.List[tp.List[str]]]:
     >>> solve(grid)
     [['5', '3', '4', '6', '7', '8', '9', '1', '2'], ['6', '7', '2', '1', '9', '5', '3', '4', '8'], ['1', '9', '8', '3', '4', '2', '5', '6', '7'], ['8', '5', '9', '7', '6', '1', '4', '2', '3'], ['4', '2', '6', '8', '5', '3', '7', '9', '1'], ['7', '1', '3', '9', '2', '4', '8', '5', '6'], ['9', '6', '1', '5', '3', '7', '2', '8', '4'], ['2', '8', '7', '4', '1', '9', '6', '3', '5'], ['3', '4', '5', '2', '8', '6', '1', '7', '9']]
     """
-    pass
+    pos = find_empty_positions(grid)
+    if pos is None:
+        return grid
+    else:
+        possible_values = find_possible_values(grid, pos)
+        for number in possible_values:
+            grid[pos[0]][pos[1]] = number
+            res = solve(grid)
+            if res:
+                return res
+            grid[pos[0]][pos[1]] = "."
 
 
 def check_solution(solution: tp.List[tp.List[str]]) -> bool:
-    """ Если решение solution верно, то вернуть True, в противном случае False """
+    """Если решение solution верно, то вернуть True, в противном случае False"""
     # TODO: Add doctests with bad puzzles
-    pass
+    arr = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
+    for i in range(0, len(solution)):
+        for j in range(0, len(solution)):
+            pos = i, j
+            if not (
+                arr == sorted(get_row(solution, pos))
+                and arr == sorted(get_col(solution, pos))
+                and arr == sorted(get_block(solution, pos))
+            ):
+                return False
+    return True
 
 
 def generate_sudoku(N: int) -> tp.List[tp.List[str]]:
@@ -156,7 +205,14 @@ def generate_sudoku(N: int) -> tp.List[tp.List[str]]:
     >>> check_solution(solution)
     True
     """
-    pass
+    grid = [["." for _ in range(9)] for _ in range(9)]
+    if N > 81:
+        N = 81
+    dots = random.sample([i for i in range(81)], 81 - N)
+    solve(grid)
+    for elem in dots:
+        grid[elem // 9][elem % 9] = "."
+    return grid
 
 
 if __name__ == "__main__":
@@ -168,3 +224,8 @@ def generate_sudoku(N: int) -> tp.List[tp.List[str]]:
             print(f"Puzzle {fname} can't be solved")
         else:
             display(solution)
+        if check_solution(solution):
+            print("Solution is correct")
+        else:
+            print("Ooops")
+    display(generate_sudoku(1))