From 8d1ddb46c45a37538b50d12baa58f7bf0d488027 Mon Sep 17 00:00:00 2001
From: pjmw9izve <2308014474@qq.com>
Date: Sun, 6 Oct 2024 13:09:45 +0800
Subject: [PATCH] ADD file via upload

---
 randomSelect.js | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 randomSelect.js

diff --git a/randomSelect.js b/randomSelect.js
new file mode 100644
index 0000000..ffda649
--- /dev/null
+++ b/randomSelect.js
@@ -0,0 +1,45 @@
+const pool = require('../db');
+
+async function selectStudent(req, res) {
+    try {
+        const connection = await pool.getConnection();
+        
+        // 从数据库查询学生
+        const [students] = await connection.query('SELECT * FROM students');
+        
+        // 计算权重的总和（使用 softmax 权重计算）
+        const totalWeight = students.reduce((acc, student) => acc + Math.exp(-student.score), 0);
+
+        // 将每个学生的权重归一化
+        const weightedStudents = students.map(student => ({
+            student,
+            weight: Math.exp(-student.score) / totalWeight,
+        }));
+
+        // 生成随机数
+        const random = Math.random();  // 介于 0 和 1 之间
+        let sum = 0;  // 用于累加权重
+        let selectedStudent = null;
+
+        // 遍历加权后的学生，累加权重，并判断随机数落在哪个学生的区间
+        for (let i = 0; i < weightedStudents.length; i++) {
+            sum += weightedStudents[i].weight;  // 累加当前学生的权重
+            if (random <= sum) {  // 如果随机数小于或等于当前的累积权重
+                selectedStudent = weightedStudents[i].student;  // 选中该学生
+                break;  // 找到后立即退出循环
+            }
+        }
+
+        if (selectedStudent) {
+            res.send({ student: selectedStudent });
+        } else {
+            res.status(404).send({ message: '无学生数据' });
+        }
+
+        connection.release();
+    } catch (error) {
+        res.status(500).send({ error: '随机选择学生失败' });
+    }
+}
+
+module.exports = { selectStudent };