Question

MergeSort.js

var merge_sort = function(unsorted) {
  if (unsorted.length <= 1)
    return unsorted;

  var middle = unsorted.length / 2; 

  var left = unsorted.slice(0, middle - 1);
  var right = unsorted.slice(middle, unsorted - 1);

  left = merge_sort(left);
  right = merge_sort(right);

  return merge(left, right);
};

var merge = function(left, right) {
  var result = [];

  while(left.length > 0 || right.length > 0)
    if(left.length > 0 && right.length > 0) {
      if (left[0] <= right[0]) {
        result.push(left.shift());
      } else {
        result.push(right.shift());
      }
    } else if(left.length > 0) {
      result.push(left.shift());
    } else if(right.length > 0) {
      result.push(right.shift());
    }
  }

  return result;
};

MergeSortSpec.js

describe("#merge_sort", function() {

  it("should sort the unsorted array", function() {
    var unsorted = [8, 2, 10, 5, 4, 9, 7, 1, 6, 3];
    var sorted = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
    expect(merge_sort(unsorted)).toEqual(sorted);
  });

});

错误消息

ReferenceError: merge_sort is not defined
    at null.<anonymous> (file://localhost/Users/jasonkim/projects/algorithm-everyday/merge_sort/javascript/spec/MergeSortSpec.js:6:12)

我不确定为什么jasmine.js告诉我merge_sort没有定义。即使它在那里。知道为什么吗？

SpecRunner.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
  "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
  <title>Jasmine Spec Runner</title>

  <link rel="shortcut icon" type="image/png" href="lib/jasmine-1.3.1/jasmine_favicon.png">
  <link rel="stylesheet" type="text/css" href="lib/jasmine-1.3.1/jasmine.css">
  <script type="text/javascript" src="lib/jasmine-1.3.1/jasmine.js"></script>
  <script type="text/javascript" src="lib/jasmine-1.3.1/jasmine-html.js"></script>

  <!-- include source files here... -->
  <script type="text/javascript" src="src/MergeSort.js"></script>

  <!-- include spec files here... -->
  <script type="text/javascript" src="spec/MergeSortSpec.js"></script>

  <script type="text/javascript">
    (function() {
      var jasmineEnv = jasmine.getEnv();
      jasmineEnv.updateInterval = 1000;

      var htmlReporter = new jasmine.HtmlReporter();

      jasmineEnv.addReporter(htmlReporter);

      jasmineEnv.specFilter = function(spec) {
        return htmlReporter.specFilter(spec);
      };

      var currentWindowOnload = window.onload;

      window.onload = function() {
        if (currentWindowOnload) {
          currentWindowOnload();
        }
        execJasmine();
      };

      function execJasmine() {
        jasmineEnv.execute();
      }

    })();
  </script>

</head>

<body>
</body>
</html>

Answer 1

问题可能是while循环开始时缺少的开括号？如果你修复它，它在茉莉花中运行良好（尽管输出不正确）

var merge = function(left, right) {
    var result = [];

    while(left.length > 0 || right.length > 0) {
        if(left.length > 0 && right.length > 0) {
            if (left[0] <= right[0]) {
               result.push(left.shift());
            } else {
               result.push(right.shift());
            }
         } else if(left.length > 0) {
            result.push(left.shift());
         } else if(right.length > 0) {
            result.push(right.shift());
         }
     }

     return result;
};

javascript：递归，方法已定义，但它继续说它没有定义

1 个答案: