https://shio-chan-dev.github.io/jeanblog/tags/deduplication/Recent content in Deduplication on Jeanphilo BlogHugo -- 0.161.1en-usSun, 03 May 2026 14:25:07 +0800https://shio-chan-dev.github.io/jeanblog/alg/leetcode/hot100/backtracking/90-subsets-ii/Sun, 03 May 2026 14:25:07 +0800https://shio-chan-dev.github.io/jeanblog/alg/leetcode/hot100/backtracking/90-subsets-ii/<h2 id="problem-requirement">Problem Requirement</h2> <h3 id="input--output">Input / Output</h3> <ul> <li>Input: <code>nums</code>, with <code>1 &lt;= nums.length &lt;= 10</code></li> <li>Value range: <code>-10 &lt;= nums[i] &lt;= 10</code></li> <li><code>nums</code> may contain duplicates</li> <li>Output: return all unique subsets</li> <li>Ordering: the result order does not matter, but the same value sequence may appear only once</li> </ul> <h3 id="example">Example</h3> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-text" data-lang="text"><span style="display:flex;"><span>Input: nums = [1,2,2] </span></span><span style="display:flex;"><span>Output: [[],[1],[1,2],[1,2,2],[2],[2,2]] </span></span></code></pre></div><p>This tutorial starts with a correct but wasteful version, then derives sorting plus layer-level deduplication.</p> <h2 id="start-from-duplicate-branches-in-122">Start From Duplicate Branches in <code>[1,2,2]</code></h2> <p>The smallest example that exposes the issue is:</p>