test: migrate LeetCode 57 to new directory structure with tests and docs

README.md

@@ -41,12 +41,12 @@ Each problem follows this structure:
 
 ## Solutions
 
-📊 **Statistics**: 85 problems solved (migrated to new structure)
+📊 **Statistics**: 86 problems solved (migrated to new structure)
 
 | Difficulty | Count |
 |------------|-------|
 | Easy       | 60    |
-| Medium     | 24    |
+| Medium     | 25    |
 | Hard       | 1     |
 
 ### Browse by Difficulty

docs/MEDIUM.md

@@ -1,6 +1,6 @@
 # Medium Problems
 
-Total: 24 problems solved
+Total: 25 problems solved
 
 ## Solutions
 
@@ -11,6 +11,7 @@ Total: 24 problems solved
 | 33 | [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/) | [solution.py](../problems/medium/search_in_rotated_sorted_array_33/solution.py) | [test_solution.py](../problems/medium/search_in_rotated_sorted_array_33/test_solution.py) |
 | 49 | [Group Anagrams](https://leetcode.com/problems/group-anagrams/) | [solution.py](../problems/medium/group_anagrams_49/solution.py) | [test_solution.py](../problems/medium/group_anagrams_49/test_solution.py) |
 | 56 | [Merge Intervals](https://leetcode.com/problems/merge-intervals/) | [solution.py](../problems/medium/merge_intervals_56/solution.py) | [test_solution.py](../problems/medium/merge_intervals_56/test_solution.py) |
+| 57 | [Insert Interval](https://leetcode.com/problems/insert-interval/) | [solution.py](../problems/medium/insert_interval_57/solution.py) | [test_solution.py](../problems/medium/insert_interval_57/test_solution.py) |
 | 62 | [Unique Paths](https://leetcode.com/problems/unique-paths/) | [solution.py](../problems/medium/unique_paths_62/solution.py) | [test_solution.py](../problems/medium/unique_paths_62/test_solution.py) |
 | 79 | [Word Search](https://leetcode.com/problems/word-search/) | [solution.py](../problems/medium/word_search_79/solution.py) | [test_solution.py](../problems/medium/word_search_79/test_solution.py) |
 | 102 | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/) | [solution.py](../problems/medium/binary_tree_level_order_traversal_102/solution.py) | [test_solution.py](../problems/medium/binary_tree_level_order_traversal_102/test_solution.py) |

problems/medium/insert_interval_57/solution.py

@@ -0,0 +1,39 @@
+# Tags: Array
+from typing import List
+
+
+class Solution:
+    def insert(self, intervals: List[List[int]], new_interval: List[int]) -> List[List[int]]:
+        """
+        Insert new_interval into sorted intervals and merge overlapping intervals.
+
+        Args:
+            intervals: List of non-overlapping intervals sorted by start time.
+                       Each interval is [start, end] where start <= end.
+            new_interval: The interval to insert, formatted as [start, end].
+
+        Returns:
+            List of non-overlapping intervals sorted by start time after insertion
+            and merging all overlapping intervals.
+
+        Time Complexity: O(n)
+        - Single pass through intervals list where n = len(intervals)
+        - Each iteration performs O(1) operations (comparisons, min/max)
+        - Worst case: process all intervals before finding insertion point
+
+        Space Complexity: O(1) auxiliary space (excluding output)
+        - Only uses constant extra variables for iteration (i)
+        - Output list 'res' is not counted as auxiliary space
+        """
+        res = []
+        for i in range(len(intervals)):
+            if new_interval[1] < intervals[i][0]:
+                res.append(new_interval)
+                return res + intervals[i:]
+            elif new_interval[0] > intervals[i][1]:
+                res.append(intervals[i])
+            else:
+                new_interval = [min(new_interval[0], intervals[i][0]),
+                                max(new_interval[1], intervals[i][1])]
+        res.append(new_interval)
+        return res

problems/medium/insert_interval_57/test_solution.py

@@ -0,0 +1,15 @@
+import pytest
+from .solution import Solution
+from tests.base_test import BaseTestSolution
+
+
+class TestSolution(BaseTestSolution):
+    solution = Solution()
+
+    @pytest.mark.parametrize("method_name, intervals, new_interval, expected, timeout", [
+        ('insert', [[1, 3], [6, 9]], [2, 5], [[1, 5], [6, 9]], BaseTestSolution.DEFAULT_TIMEOUT),
+        ('insert', [[1, 2], [3, 5], [6, 7], [8, 10], [12, 16]], [4, 8], [[1, 2], [3, 10], [12, 16]],
+         BaseTestSolution.DEFAULT_TIMEOUT),
+    ])
+    def test_insert(self, method_name, intervals, new_interval, expected, timeout):
+        self._run_test(self.solution, method_name, (intervals, new_interval,), expected, timeout)