JavaScript 二分查找 w/out 数组

Question

我正在尝试使用 JavaScript 创建一个数字猜谜游戏来进行代码挑战，我对这门语言还很陌生，需要一些帮助。

游戏的前提是让电脑猜猜用户的号码在0到100之间。参数是使用if-else语句和while循环中的确认函数。建议使用将在循环中移动的二进制搜索（不使用和数组）；通过询问用户他们的数字是否高于、低于或等于计算机当前的猜测来缩小计算机的猜测范围。

正如您在下面看到的，我能够启动 if 语句并在用户确认该语句为真时给出结果。但现在我卡在了如何继续 else if 语句，继续循环，并成功实现二分查找。我已经开始了 else if 语句，但我知道这很可能不是要走的路。我试图通过堆栈溢出和其他站点搜索如何使用二进制搜索，但是所有结果都是通过数组使用它返回的，这是我做不到的。任何帮助和建议将不胜感激。

var guessNumGame = function () {
 'use strict';
 var low = 0;
 var high = 100;
 var number;

 alert("Think of a number betwwen 0 and 100");
 while (low <= high) {
  number = Math.round((low + high) / 2);

  if (window.confirm("Is your number " + number + " ? Click OK for 
        Yes, CANCEL for No.") == true ) {

    alert("You got it! Thanks for playing!");

  } //this is where I'm stuck on how to proceed and below is unfinished

        else if (window.confirm("Is your number higher or lower? Click OK 
        for higher, CANCEL for lower. ") < true) {

    window.confirm("Is your number " + number / 2 + " ? Click OK 
             for Yes, CANCEL for No.") == true;

  }else {

   return guess;
  }

   return; // this return is here just to avoid and infinite loop
 }

};

window.onload = guessNumGame;

<!DOCTYPE HTML>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Pick a Number</title>
    <meta name="description" content="">
    <meta name="viewport" content="width=device-width, initial-scale=1">
  </head>
  <body>
    <h1>Pick a number for me to guess</h1>
    <script src="js/pick_number.js"></script>
  </body>
</html>

Answer 1

您可以将 while 循环与 confirm 语句结合使用，以简单的方式创建它。

备注：

我已将确认包装在辅助函数中以提高代码可读性。
我在询问它是否较高后跳过了检查它是否较低的提示，因为它是多余的。

样本

function guessNumber(number) {
  return confirm('Is ' + number + ' your number?');
}

function askIfHigher(number) {
  return confirm('Is your number greater than ' + number + '?');
}

function startGame() {
  // Initialise variables
  var low = 0,
    high = 100,
    mid,
    complete = false;

  // Repeat while we have not guessed the answer or binary search fails
  while (!complete && (low <= high)) {
    // Guess number
    mid = Math.floor((low + high) / 2);
    complete = guessNumber(mid);
    if(complete){
      // Guess is correct, exit while loop
      break;
    }
    // Guess is incorrect adjust binary search parameters as needed
    if (askIfHigher(mid)) {
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }
  if(!complete){
    // Binary search terminated without getting a result
    alert('You must have picked a number outisde of 0-100');
  }else{
    alert('Congratulations! your number was: '+mid);
  }

}

startGame();

Answer 2

这段代码实现了你的想法，你想要实现的很有趣！但是实现它的想法似乎并不方便。

var guessNumGame = function () {
 'use strict';
 var low = 0;
 var high = 100;
 var number;

 alert("Think of a number betwwen 0 and 100");
 while (low <= high) {
     number = Math.floor((Math.random() * (high - low + 1))) + low;
  if (window.confirm("Is your number " + number + " ? Click OK for Yes, CANCEL for No."))
    return alert("YAAAY! I WON");
      if (window.confirm("Is your number higher or lower? Click OK for higher, CANCEL for lower. ")) {
   low = number + 1;
  } else {
   high = number - 1;
  }
 }

};

guessNumGame();

JavaScript 二分查找 w/out 数组

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