feat: add 2 more leetcode problems (#66)

Author: wislertt

leetcode/decode_ways/README.md

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+# Decode Ways
+
+**Difficulty:** Medium
+**Topics:** String, Dynamic Programming
+**Tags:** blind-75
+
+**LeetCode:** [Problem 91](https://leetcode.com/problems/decode-ways/description/)
+
+## Problem Description
+
+You have intercepted a secret message encoded as a string of numbers. The message is decoded via the mapping: `"1" -> 'A', "2" -> 'B', ..., "26" -> 'Z'`. Given a string `s` containing only digits, return the number of ways to decode it. Return `0` if it cannot be decoded.
+
+## Examples
+
+### Example 1:
+
+```
+Input: s = "12"
+Output: 2
+Explanation: "12" could be decoded as "AB" (1 2) or "L" (12).
+```
+
+### Example 2:
+
+```
+Input: s = "226"
+Output: 3
+Explanation: "226" could be decoded as "BZ" (2 26), "VF" (22 6), or "BBF" (2 2 6).
+```
+
+### Example 3:
+
+```
+Input: s = "06"
+Output: 0
+Explanation: leading zero makes it invalid.
+```
+
+## Constraints
+
+- 1 <= s.length <= 100
+- s contains only digits and may contain leading zero(s)

leetcode/decode_ways/__init__.py

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+def run_num_decodings(solution_class: type, s: str):
+    implementation = solution_class()
+    return implementation.num_decodings(s)
+
+
+def assert_num_decodings(result: int, expected: int) -> bool:
+    assert result == expected
+    return True

leetcode/decode_ways/helpers.py

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+# ---
+# jupyter:
+#   jupytext:
+#     text_representation:
+#       extension: .py
+#       format_name: percent
+#       format_version: '1.3'
+#       jupytext_version: 1.17.3
+#   kernelspec:
+#     display_name: leetcode-py-py3.13
+#     language: python
+#     name: python3
+# ---
+
+# %%
+from helpers import assert_num_decodings, run_num_decodings
+from solution import Solution
+
+# %%
+# Example test case
+s = "226"
+expected = 3
+
+# %%
+result = run_num_decodings(Solution, s)
+result
+
+# %%
+assert_num_decodings(result, expected)

leetcode/decode_ways/playground.py

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+class Solution:
+
+    # Time: O(n)
+    # Space: O(1)
+    def num_decodings(self, s: str) -> int:
+        if not s:
+            return 0
+
+        num_ways_two_steps_behind: int = 1
+        num_ways_one_step_behind: int = 0 if s[0] == "0" else 1
+
+        for index in range(1, len(s)):
+            current_char: str = s[index]
+            previous_char: str = s[index - 1]
+
+            current_num_ways: int = 0
+
+            if current_char != "0":
+                current_num_ways += num_ways_one_step_behind
+
+            two_digit_value: int = int(previous_char + current_char)
+            if previous_char != "0" and 10 <= two_digit_value <= 26:
+                current_num_ways += num_ways_two_steps_behind
+
+            num_ways_two_steps_behind, num_ways_one_step_behind = (
+                num_ways_one_step_behind,
+                current_num_ways,
+            )
+
+        return num_ways_one_step_behind

leetcode/decode_ways/solution.py

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+import pytest
+
+from leetcode_py import logged_test
+
+from .helpers import assert_num_decodings, run_num_decodings
+from .solution import Solution
+
+
+class TestDecodeWays:
+    def setup_method(self):
+        self.solution = Solution()
+
+    @logged_test
+    @pytest.mark.parametrize(
+        "s, expected",
+        [
+            ("12", 2),
+            ("226", 3),
+            ("06", 0),
+            ("0", 0),
+            ("10", 1),
+            ("27", 1),
+            ("101", 1),
+            ("100", 0),
+            ("110", 1),
+            ("2101", 1),
+            ("2611055971756562", 4),
+            ("1", 1),
+            ("30", 0),
+        ],
+    )
+    def test_num_decodings(self, s: str, expected: int):
+        result = run_num_decodings(Solution, s)
+        assert_num_decodings(result, expected)

leetcode/decode_ways/test_solution.py

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+# Set Matrix Zeroes
+
+**Difficulty:** Medium
+**Topics:** Array, Hash Table, Matrix
+**Tags:** blind-75
+
+**LeetCode:** [Problem 73](https://leetcode.com/problems/set-matrix-zeroes/description/)
+
+## Problem Description
+
+Given an `m x n` integer matrix `matrix`, if an element is `0`, set its entire row and column to `0`'s. You must do it in place.
+
+## Examples
+
+### Example 1:
+
+![Example 1](https://assets.leetcode.com/uploads/2020/08/17/mat1.jpg)
+
+```
+Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
+Output: [[1,0,1],[0,0,0],[1,0,1]]
+```
+
+### Example 2:
+
+![Example 2](https://assets.leetcode.com/uploads/2020/08/17/mat2.jpg)
+
+```
+Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
+Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
+```
+
+## Constraints
+
+- m == matrix.length
+- n == matrix[i].length
+- 1 <= m, n <= 200
+- -2^31 <= matrix[i][j] <= 2^31 - 1
+
+- Follow up: Could you devise a constant space solution?

leetcode/set_matrix_zeroes/README.md

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+def run_set_zeroes(solution_class: type, matrix: list[list[int]]):
+    import copy
+
+    matrix_copy = copy.deepcopy(matrix)
+    implementation = solution_class()
+    implementation.set_zeroes(matrix_copy)
+    return matrix_copy
+
+
+def assert_set_zeroes(result: list[list[int]], expected: list[list[int]]) -> bool:
+    assert result == expected
+    return True

leetcode/set_matrix_zeroes/__init__.py

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+# ---
+# jupyter:
+#   jupytext:
+#     text_representation:
+#       extension: .py
+#       format_name: percent
+#       format_version: '1.3'
+#       jupytext_version: 1.17.3
+#   kernelspec:
+#     display_name: leetcode-py-py3.13
+#     language: python
+#     name: python3
+# ---
+
+# %%
+from helpers import assert_set_zeroes, run_set_zeroes
+from solution import Solution
+
+# %%
+# Example test case
+matrix = [[1, 1, 1], [1, 0, 1], [1, 1, 1]]
+expected = [[1, 0, 1], [0, 0, 0], [1, 0, 1]]
+
+# %%
+result = run_set_zeroes(Solution, matrix)
+result
+
+# %%
+assert_set_zeroes(result, expected)