Hide TopCoder problem archive categories

Hides the category list in the topcoder problem archive, because knowing the categories of a problem can spoil the solution! (The categories are replaced with '...', click on them to toggle hidden-ness.)

2015-06-20 يوللانغان نەشرى. ئەڭ يېڭى نەشرىنى كۆرۈش.

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        Hide TopCoder problem archive categories
// @namespace   kunaifirestuff
// @description Hides the category list in the topcoder problem archive, because knowing the categories of a problem can spoil the solution! (The categories are replaced with '...', click on them to toggle hidden-ness.)
// @include     http://community.topcoder.com/tc?module=ProblemArchive*
// @version     1
// @grant       none
// ==/UserScript==

var table = document.getElementsByTagName('b') [0].parentElement.parentElement.parentElement.parentElement;
var categoryArray = new Array(table.childElementCount - 9);
var hiddenText = '...';

for (var i = 3; i < table.childElementCount - 6; i++) {
  (function (i) {
    var cats = table.children[i].children[5];
    
    categoryArray[i - 3] = cats.textContent;
    cats.textContent = hiddenText;
    cats.setAttribute('align', 'center');
    
    cats.addEventListener('click', function () {
      if (cats.textContent == hiddenText) {
        cats.textContent = categoryArray[i - 3];
      } else {
        cats.textContent = hiddenText;
      }
    });
  }(i));
}