problem: 0128. Longest Consecutive Sequence

Author: flynnpark

solutions/solution_0128/README.md

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+# 0128. [Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/?envType=study-plan-v2&envId=top-interview-150)
+
+Given an unsorted array of integers `nums`, return _the length of the longest consecutive elements sequence_.
+
+You must write an algorithm that runs in `O(n)` time.
+
+### **Example 1:**
+
+<pre><code>
+<strong>Input:</strong> nums = [100,4,200,1,3,2]
+<strong>Output:</strong> 4
+<strong>Explanation:</strong> The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is
+4.
+</code></pre>
+
+### **Example 2:**
+
+<pre><code>
+<strong>Input:</strong> nums = [0,3,7,2,5,8,4,6,0,1]
+<strong>Output:</strong> 9
+</code></pre>
+
+### **Constraints:**
+
+- <code>0 <= nums.length <= 10<sup>5</sup></code>
+- <code>-10<sup>9</sup> <= nums[i] <= 10<sup>9</sup></code>

solutions/solution_0128/__init__.py

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+class Solution:
+    def longestConsecutive(self, nums: list[int]) -> int: ...

solutions/solution_0128/test_solution.py

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+from typing import TypedDict
+
+import pytest
+
+from . import Solution
+
+
+class InputDict(TypedDict):
+    nums: list[int]
+
+
+class CaseDict(TypedDict):
+    input: InputDict
+    expected: int
+
+
+test_cases: list[CaseDict] = [
+    {
+        'input': {
+            'nums': [100, 4, 200, 1, 3, 2],
+        },
+        'expected': 4,
+    },
+    {
+        'input': {
+            'nums': [0, 3, 7, 2, 5, 8, 4, 6, 0, 1],
+        },
+        'expected': 9,
+    },
+    {
+        'input': {
+            'nums': [0, 3, 7, 2, 5, 8, 4, 6, 0, 1, 2, 3, 4, 5, 6, 7, 8],
+        },
+        'expected': 9,
+    },
+]
+
+
+@pytest.mark.parametrize(
+    'test_case',
+    test_cases,
+)
+def test_solution(test_case: CaseDict):
+    result = Solution().longestConsecutive(**test_case['input'])
+    assert result == test_case['expected']