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