Add Python file with SQL solution for problem 3764 (frontend compatibility)

Author: vikahaze

solutions/3764/01.py

@@ -0,0 +1,62 @@
+# Solution for LeetCode 3764: Most Common Course Pairs
+# Find skill mastery pathways by analyzing course completion sequences among top-performing students
+
+"""
+SQL Solution:
+
+WITH top_performers AS (
+    -- Step 1: Identify top-performing students
+    -- Must have at least 5 courses with average rating >= 4
+    SELECT 
+        user_id
+    FROM 
+        course_completions
+    GROUP BY 
+        user_id
+    HAVING 
+        COUNT(*) >= 5 
+        AND AVG(course_rating) >= 4
+),
+ordered_courses AS (
+    -- Step 2: Get courses for top performers in chronological order
+    SELECT 
+        cc.user_id,
+        cc.course_name,
+        cc.completion_date,
+        ROW_NUMBER() OVER (
+            PARTITION BY cc.user_id 
+            ORDER BY cc.completion_date
+        ) AS course_order
+    FROM 
+        course_completions cc
+    INNER JOIN 
+        top_performers tp ON cc.user_id = tp.user_id
+),
+course_pairs AS (
+    -- Step 3: Create consecutive course pairs
+    SELECT 
+        oc1.course_name AS first_course,
+        oc2.course_name AS second_course
+    FROM 
+        ordered_courses oc1
+    INNER JOIN 
+        ordered_courses oc2 
+        ON oc1.user_id = oc2.user_id 
+        AND oc2.course_order = oc1.course_order + 1
+)
+-- Step 4: Count pair frequencies and order results
+SELECT 
+    first_course,
+    second_course,
+    COUNT(*) AS transition_count
+FROM 
+    course_pairs
+GROUP BY 
+    first_course, 
+    second_course
+ORDER BY 
+    transition_count DESC,
+    first_course ASC,
+    second_course ASC;
+"""
+