LeetcodePickOneFilter.js

// ==UserScript==
// @name         Leetcode "PickOne" filter
// @namespace    https://leetcode.com/
// @version      0.1
// @description  Apply table filters also to "PickOne" button in "Problems" section
// @author       Paolo Simone
// @match        https://leetcode.com/problemset/*
// @grant        none
// ==/UserScript==

(function() {
  let onClick = function() {
    let problems = document.querySelectorAll("tbody.reactable-data > tr > td > div > a");
    problems = Array.from(problems).filter(a => a.parentElement.querySelector("span i.fa-lock") == null);
    let random = Math.floor(Math.random() * Math.floor(problems.length));
    window.open(problems[random].href, '_blank');
  }

  window.addEventListener('load', function() {
    let pickOneBtn = document.querySelector("div.assess-bar > div.pull-right > span.pick-one-btn > a");
    pickOneBtn.removeAttribute("href");
    pickOneBtn.addEventListener("click", onClick);
  }, false);
})();