{"id":6897,"date":"2025-06-17T19:57:32","date_gmt":"2025-06-17T14:27:32","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=6897"},"modified":"2025-06-17T19:57:33","modified_gmt":"2025-06-17T14:27:33","slug":"intersection-of-two-linked-lists","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/intersection-of-two-linked-lists\/","title":{"rendered":"Intersection of Two Linked Lists"},"content":{"rendered":"\n<!-- PrismJS for Syntax Highlighting -->\n<link href=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/themes\/prism-tomorrow.min.css\" rel=\"stylesheet\">\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/prism.min.js\"><\/script>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/plugins\/autoloader\/prism-autoloader.min.js\"><\/script>\n\n<style>\n  .wp_blog_main-heading {\n    text-align: center;\n    font-size: 2.4rem;\n    color: #E58C32;\n    margin-top: 2.5rem;\n    font-weight: bold;\n  }\n\n  .wp_blog_explanation,\n  .wp_blog_code-tabs-container {\n    max-width: 940px;\n    margin: 2rem auto;\n    padding: 2rem;\n    border-radius: 12px;\n    background-color: #f9fafb;\n  }\n\n  .wp_blog_explanation h2 {\n    font-size: 1.4rem;\n    color: #E58C32;\n    margin-bottom: 0.75rem;\n  }\n\n  .wp_blog_explanation p,\n  .wp_blog_explanation li {\n    font-size: 1.05rem;\n    line-height: 1.7;\n    margin: 0.5rem 0;\n    color: #1f2937;\n  }\n\n  .wp_blog_explanation code {\n    padding: 3px 6px;\n    border-radius: 4px;\n    background: #e5e7eb;\n    font-family: 'Courier New', monospace;\n  }\n\n  .wp_blog_code-tabs-header {\n    display: flex;\n    flex-wrap: wrap;\n    gap: 0.5rem;\n    margin-bottom: 1rem;\n  }\n\n  .wp_blog_code-tab-button {\n    padding: 0.6rem 1.2rem;\n    border: 1px solid #E58C32;\n    color: #E58C32;\n    border-radius: 50px;\n    font-weight: 600;\n    cursor: pointer;\n    background-color: white;\n    transition: background 0.3s ease, color 0.3s ease;\n  }\n\n  .wp_blog_code-tab-button.active {\n    background: #E58C32;\n    color: white;\n  }\n\n  .wp_blog_code-tab-content {\n    display: none;\n    background: #111827;\n    border-radius: 12px;\n  }\n\n  .wp_blog_code-tab-content.active {\n    display: block;\n  }\n\n  .wp_blog_code-tab-content pre {\n    margin: 0;\n    padding: 1.5rem;\n    font-size: 1rem;\n    overflow-x: auto;\n    color: #f3f4f6;\n    background: #111827;\n    border-radius: 12px;\n  }\n<\/style>\n\n<div class=\"wp_blog_explanation\">\n  <h2>Problem Statement:<\/h2>\n  <p>Given the heads of two singly linked-lists <code>headA<\/code> and <code>headB<\/code>, return the node at which the two lists intersect. If the two linked lists have no intersection at all, return <code>null<\/code>.<\/p>\n\n  <h2>Examples:<\/h2>\n  <ul>\n    <li><strong>Input:<\/strong> intersectVal = 8, listA = [4,1,8,4,5], listB = [5,6,1,8,4,5], skipA = 2, skipB = 3<br><strong>Output:<\/strong> Intersected at &#8216;8&#8217;<\/li>\n    <li><strong>Input:<\/strong> intersectVal = 2, listA = [1,9,1,2,4], listB = [3,2,4], skipA = 3, skipB = 1<br><strong>Output:<\/strong> Intersected at &#8216;2&#8217;<\/li>\n    <li><strong>Input:<\/strong> intersectVal = 0, listA = [2,6,4], listB = [1,5], skipA = 3, skipB = 2<br><strong>Output:<\/strong> No intersection<\/li>\n  <\/ul>\n\n  <h2>Constraints:<\/h2>\n  <ul>\n    <li>The number of nodes in each list is in the range [0, 10\u2074].<\/li>\n    <li>-10\u2075 \u2264 Node.val \u2264 10\u2075<\/li>\n    <li>Lists are guaranteed to be acyclic and maintain their structure.<\/li>\n  <\/ul>\n\n  <h2>Approach:<\/h2>\n  <ul>\n    <li>Store all nodes of <code>headB<\/code> in a <code>Set<\/code>.<\/li>\n    <li>Traverse <code>headA<\/code>; return the node when one exists in the set.<\/li>\n    <li>If no match is found, return <code>null<\/code>.<\/li>\n  <\/ul>\n\n  <h2>Time and Space Complexity:<\/h2>\n  <ul>\n    <li><strong>Time Complexity:<\/strong> O(n + m), where n and m are lengths of listA and listB.<\/li>\n    <li><strong>Space Complexity:<\/strong> O(m), storing nodes of listB in a set.<\/li>\n  <\/ul>\n<\/div>\n\n<div class=\"wp_blog_code-tabs-container\">\n  <div class=\"wp_blog_code-tabs-header\">\n    <button class=\"wp_blog_code-tab-button active\" data-lang=\"js\">JavaScript<\/button>\n    <button class=\"wp_blog_code-tab-button\" data-lang=\"py\">Python<\/button>\n    <button class=\"wp_blog_code-tab-button\" data-lang=\"java\">Java<\/button>\n    <button class=\"wp_blog_code-tab-button\" data-lang=\"cpp\">C++<\/button>\n    <button class=\"wp_blog_code-tab-button\" data-lang=\"c\">C<\/button>\n    <button class=\"wp_blog_code-tab-button\" data-lang=\"cs\">C#<\/button>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content active\" data-lang=\"js\">\n    <pre><code class=\"language-javascript\">\nvar getIntersectionNode = function(headA, headB) {\n    let set = new Set();\n    while (headB) {\n        set.add(headB);\n        headB = headB.next;\n    }\n    while (headA) {\n        if (set.has(headA)) return headA;\n        headA = headA.next;\n    }\n    return null;\n};\n    <\/code><\/pre>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content\" data-lang=\"py\">\n    <pre><code class=\"language-python\">\nclass Solution(object):\n    def getIntersectionNode(self, headA, headB):\n        visited = set()\n        while headB:\n            visited.add(headB)\n            headB = headB.next\n        while headA:\n            if headA in visited:\n                return headA\n            headA = headA.next\n        return None\n    <\/code><\/pre>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content\" data-lang=\"java\">\n    <pre><code class=\"language-java\">\npublic class Solution {\n    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {\n        Set<ListNode> visited = new HashSet<>();\n        while (headB != null) {\n            visited.add(headB);\n            headB = headB.next;\n        }\n        while (headA != null) {\n            if (visited.contains(headA)) return headA;\n            headA = headA.next;\n        }\n        return null;\n    }\n}\n    <\/code><\/pre>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content\" data-lang=\"cpp\">\n    <pre><code class=\"language-cpp\">\nclass Solution {\npublic:\n    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {\n        unordered_set&ltListNode*&gt visited;\n        while (headB) {\n            visited.insert(headB);\n            headB = headB->next;\n        }\n        while (headA) {\n            if (visited.count(headA)) return headA;\n            headA = headA->next;\n        }\n        return nullptr;\n    }\n};\n    <\/code><\/pre>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content\" data-lang=\"c\">\n    <pre><code class=\"language-c\">\nstruct ListNode* getIntersectionNode(struct ListNode *headA, struct ListNode *headB) {\n    while (headA) {\n        struct ListNode *temp = headB;\n        while (temp) {\n            if (temp == headA) return headA;\n            temp = temp->next;\n        }\n        headA = headA->next;\n    }\n    return NULL;\n}\n    <\/code><\/pre>\n  <\/div>\n\n  <div class=\"wp_blog_code-tab-content\" data-lang=\"cs\">\n    <pre><code class=\"language-csharp\">\npublic class Solution {\n    public ListNode GetIntersectionNode(ListNode headA, ListNode headB) {\n        HashSet&ltListNode&gt visited = new HashSet&ltListNode&gt();\n        while (headB != null) {\n            visited.Add(headB);\n            headB = headB.next;\n        }\n        while (headA != null) {\n            if (visited.Contains(headA)) return headA;\n            headA = headA.next;\n        }\n        return null;\n    }\n}\n    <\/code><\/pre>\n  <\/div>\n<\/div>\n\n<script>\n  document.addEventListener('DOMContentLoaded', () => {\n    const buttons = document.querySelectorAll('.wp_blog_code-tab-button');\n    const contents = document.querySelectorAll('.wp_blog_code-tab-content');\n    buttons.forEach(button => {\n      button.addEventListener('click', () => {\n        const lang = button.getAttribute('data-lang');\n        buttons.forEach(btn => btn.classList.remove('active'));\n        contents.forEach(content => content.classList.remove('active'));\n        button.classList.add('active');\n        document.querySelector(`.wp_blog_code-tab-content[data-lang=\"${lang}\"]`).classList.add('active');\n      });\n    });\n  });\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Problem Statement: Given the heads of two singly linked-lists headA and headB, return the node at which the two lists intersect. If the two linked lists have no intersection at all, return null. Examples: Input: intersectVal = 8, listA = [4,1,8,4,5], listB = [5,6,1,8,4,5], skipA = 2, skipB = 3Output: Intersected at &#8216;8&#8217; Input: intersectVal<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[260,176,811,810,174,172,173],"tags":[],"class_list":["post-6897","post","type-post","status-publish","format-standard","category-c-c-plus-plus","category-csharp","category-data-structures-and-algorithms","category-dsa","category-java","category-javascript","category-python"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/6897","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/comments?post=6897"}],"version-history":[{"count":1,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/6897\/revisions"}],"predecessor-version":[{"id":6898,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/6897\/revisions\/6898"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=6897"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=6897"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=6897"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}