feat: add problem name distribution and problem×class matrix to statistics

app/routes/students.py

@@ -432,6 +432,25 @@ def get_student_statistics():
             "problem_count": len(class_problems)
         })
 
+    # 各问题名称分布
+    problem_name_dist = {}
+    for p in problems:
+        name = p.problem.name if p.problem else f"问题{p.problem_id}"
+        if name not in problem_name_dist:
+            problem_name_dist[name] = 0
+        problem_name_dist[name] += 1
+    # 排序：数量多的在前
+    problem_name_dist = dict(sorted(problem_name_dist.items(), key=lambda x: x[1], reverse=True))
+
+    # 问题×班级矩阵
+    problem_class_matrix = []
+    for p_name in problem_name_dist.keys():
+        row = {"problem_name": p_name}
+        for c in classes:
+            count = sum(1 for p in problems if (p.problem.name if p.problem else f"问题{p.problem_id}") == p_name and p.student.class_id == c.id)
+            row[f"class_{c.id}"] = count
+        problem_class_matrix.append(row)
+
     return jsonify({
         "total_students": total_students,
         "total_problems": len(problems),
@@ -440,4 +459,7 @@ def get_student_statistics():
         "class_student_count": class_student_count,
         "class_problem_count": class_problem_count,
         "problem_level_matrix": matrix,
+        "problem_name_distribution": problem_name_dist,
+        "problem_class_matrix": problem_class_matrix,
+        "classes": [{"id": c.id, "name": c.name} for c in classes],
     })