vace/index.html

## index.html
<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <!--author:Vace_Vlm(ocdo@qq.com),create:15 Jan 2021 11:17 AM-->
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
  <meta name="renderer" content="webkit">
  <meta http-equiv="Cache-Control" content="no-siteapp" />
  <meta name="apple-mobile-web-app-title" content="vace" />
  <meta name="format-detection" content="telephone=no" />
  <meta name="msapplication-tap-highlight" content="no" />
  <meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no, viewport-fit=cover">
  <title>验证演示程序</title>
</head>
<body>
  <div id="app">
    <p>三个门A B C后面 只有一个门放着奖品。主持人让你选。在你做完选择后 （假设你选A），主持人打开另外两扇门中没有奖品的那一扇门 （假设打开了B），这时候问你 你是坚持选 A还是换成C。</p>
    <pre id="output"></pre>
  </div>
  <script>
    console.log = function (...args) {
      const inner = args.map(t => `<span>${t}</span>`).join(' ') || ' '
      const div = document.createElement('div')
      div.innerHTML = inner
      output.appendChild(div)
    }
  </script>
  <script src="main.js"></script>
  <!-- built files will be auto injected -->
</body>
</html>

## main.js
// node main.js

console.log('❓无论B是否为空，都不更换A选项')
bayes({ count: 10000, isExchange: false, isKnow: false })

console.log('❓只要B是空的就更换为C选项')
bayes({ count: 10000, isExchange: true, isKnow: false })

console.log('❓主持人知道B或者C的空箱，打开空箱则更换为另外一个')
bayes({ count: 10000, isExchange: true, isKnow: true })


function bayes (config) {
  const { count, isExchange, isKnow } = config
  const A = 0, B = 1, C = 2
  const rewards = [0, 0, 1]
  const counts = { max: count, hit: 0, change: 0 }
  for (var i = 0; i < count; i++) {
    shuffle(rewards)
    // 用户选择 A 中的奖品
    var checked = rewards[A]
    if (isExchange) {
      // 主持人明确知道B或者C中的空箱
      if (isKnow) {
        if (!rewards[B]) {
          checked = rewards[C]
          counts.change += 1
        }
        else if (!rewards[C]) {
          checked = rewards[B]
          counts.change += 1
        }
      } else {
        // 主持人不知道是否为空箱，只打开B箱，如果奖品在B中，则失败，不在B中则切换
        if (!rewards[B]) {
          checked = rewards[C]
          counts.change += 1
        }
      }
    }
    if (checked) {
      counts.hit += 1
    }
  }
  console.log('抽奖次数：', counts.max)
  console.log('是否交换：', config.isExchange ? '交换' : '不交换')
  console.log('是否之情：', config.isKnow ? '主持人明确知道B或C中的空箱' : '主持人被蒙在鼓里')
  console.log('更换次数：', counts.change)
  console.log('中奖次数：', counts.hit)
  console.log('获奖概率：', (counts.hit / counts.max * 100).toFixed(2) + '%')
  console.log()
}


function random (max) {
  return Math.floor(Math.random() * max)
}

function shuffle(array) {
  var currentIndex = array.length, temporaryValue, randomIndex;
  while (0 !== currentIndex) {
    randomIndex = random(currentIndex);
    currentIndex -= 1;
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }
  return array;
}
	<!DOCTYPE html>
	<html lang="zh-CN">
	<head>
	<!--author:Vace_Vlm(ocdo@qq.com),create:15 Jan 2021 11:17 AM-->
	<meta charset="UTF-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
	<meta name="renderer" content="webkit">
	<meta http-equiv="Cache-Control" content="no-siteapp" />
	<meta name="apple-mobile-web-app-title" content="vace" />
	<meta name="format-detection" content="telephone=no" />
	<meta name="msapplication-tap-highlight" content="no" />
	<meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no, viewport-fit=cover">
	<title>验证演示程序</title>
	</head>
	<body>
	<div id="app">
	<p>三个门A B C后面只有一个门放着奖品。主持人让你选。在你做完选择后（假设你选A），主持人打开另外两扇门中没有奖品的那一扇门（假设打开了B），这时候问你你是坚持选 A还是换成C。</p>
	<pre id="output"></pre>
	</div>
	<script>
	console.log = function (...args) {
	const inner = args.map(t => `<span>${t}</span>`).join(' ') \|\| ' '
	const div = document.createElement('div')
	div.innerHTML = inner
	output.appendChild(div)
	}
	</script>
	<script src="main.js"></script>
	<!-- built files will be auto injected -->
	</body>
	</html>
	// node main.js

	console.log('❓无论B是否为空，都不更换A选项')
	bayes({ count: 10000, isExchange: false, isKnow: false })

	console.log('❓只要B是空的就更换为C选项')
	bayes({ count: 10000, isExchange: true, isKnow: false })

	console.log('❓主持人知道B或者C的空箱，打开空箱则更换为另外一个')
	bayes({ count: 10000, isExchange: true, isKnow: true })


	function bayes (config) {
	const { count, isExchange, isKnow } = config
	const A = 0, B = 1, C = 2
	const rewards = [0, 0, 1]
	const counts = { max: count, hit: 0, change: 0 }
	for (var i = 0; i < count; i++) {
	shuffle(rewards)
	// 用户选择 A 中的奖品
	var checked = rewards[A]
	if (isExchange) {
	// 主持人明确知道B或者C中的空箱
	if (isKnow) {
	if (!rewards[B]) {
	checked = rewards[C]
	counts.change += 1
	}
	else if (!rewards[C]) {
	checked = rewards[B]
	counts.change += 1
	}
	} else {
	// 主持人不知道是否为空箱，只打开B箱，如果奖品在B中，则失败，不在B中则切换
	if (!rewards[B]) {
	checked = rewards[C]
	counts.change += 1
	}
	}
	}
	if (checked) {
	counts.hit += 1
	}
	}
	console.log('抽奖次数：', counts.max)
	console.log('是否交换：', config.isExchange ? '交换' : '不交换')
	console.log('是否之情：', config.isKnow ? '主持人明确知道B或C中的空箱' : '主持人被蒙在鼓里')
	console.log('更换次数：', counts.change)
	console.log('中奖次数：', counts.hit)
	console.log('获奖概率：', (counts.hit / counts.max * 100).toFixed(2) + '%')
	console.log()
	}


	function random (max) {
	return Math.floor(Math.random() * max)
	}

	function shuffle(array) {
	var currentIndex = array.length, temporaryValue, randomIndex;
	while (0 !== currentIndex) {
	randomIndex = random(currentIndex);
	currentIndex -= 1;
	temporaryValue = array[currentIndex];
	array[currentIndex] = array[randomIndex];
	array[randomIndex] = temporaryValue;
	}
	return array;
	}