{"id":7480,"date":"2025-07-02T15:10:00","date_gmt":"2025-07-02T09:40:00","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=7480"},"modified":"2025-07-22T21:45:10","modified_gmt":"2025-07-22T16:15:10","slug":"largest-odd-number-in-a-string","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/largest-odd-number-in-a-string\/","title":{"rendered":"Largest Odd Number in a String"},"content":{"rendered":"\n<!-- Prism.js CSS and JS -->\n<link\n  href=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/themes\/prism-tomorrow.css\"\n  rel=\"stylesheet\"\n\/>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/prism.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_code-tabs-container {\n    font-family: \"Segoe UI\", sans-serif !important;\n    max-width: 900px !important;\n    margin: 2rem auto !important;\n    border: 1px solid #ddd !important;\n    border-radius: 8px !important;\n    overflow: hidden !important;\n    background-color: white !important;\n  }\n\n  .wp_blog_code-tabs-header {\n    background: #f7f7f7 !important;\n    display: flex !important;\n    border-bottom: 1px solid #ddd !important;\n  }\n\n  .wp_blog_code-tab-button {\n    flex: 1 !important;\n    padding: 10px 15px !important;\n    border: none !important;\n    background: transparent !important;\n    cursor: pointer !important;\n    font-weight: bold !important;\n    transition: background 0.2s !important;\n    color: #242b33 !important;\n  }\n\n  .wp_blog_code-tab-button.active {\n    background: white !important;\n    border-bottom: 3px solid #0073aa !important;\n  }\n\n  .wp_blog_code-tab-content {\n    display: none !important;\n    padding: 20px !important;\n    background: #242b33 !important;\n  }\n\n  .wp_blog_code-tab-content > pre {\n    background: #242b33 !important;\n  }\n\n  .wp_blog_code-tab-content.active {\n    display: block !important;\n  }\n\n  .wp_blog_code-tab-content pre {\n    margin: 0 !important;\n    overflow-x: auto !important;\n  }\n\n  .wp_blog_explanation {\n    max-width: 900px !important;\n    margin: 2rem auto !important;\n    font-family: \"Segoe UI\", sans-serif !important;\n    line-height: 1.6 !important;\n    background: white !important;\n    color: black !important;\n    padding: 1rem !important;\n    border-radius: 8px !important;\n  }\n\n  .wp_blog_explanation h2 {\n    color: #0073aa !important;\n    font-size: 1.5rem !important;\n    margin-bottom: 0.5rem !important;\n  }\n\n  .wp_blog_explanation code {\n    background: #f1f1f1 !important;\n    padding: 2px 6px !important;\n    border-radius: 4px !important;\n    font-family: monospace !important;\n  }\n\n  .wp_blog_explanation h1,\n  .wp_blog_explanation h2,\n  .wp_blog_explanation h3,\n  .wp_blog_explanation h4,\n  .wp_blog_explanation h5,\n  .wp_blog_explanation h6,\n  .wp_blog_explanation p {\n    margin-top: 10px !important;\n    margin-bottom: 10px !important;\n  }\n<\/style>\n\n\n<div class=\"wp_blog_explanation\">\n    <p>\n      The task is to find the largest-valued odd number that can be formed from a given numeric string by removing trailing even digits. The number must be a substring starting from index 0 to some valid index.\n    <\/p>\n  \n    <h2>Steps<\/h2>\n    <ul>\n      <li>Start from the end of the string and move backward.<\/li>\n      <li>Check if the current digit is odd using modulus <code>% 2<\/code>.<\/li>\n      <li>If an odd digit is found, return the substring from index 0 to that digit (inclusive).<\/li>\n      <li>If no odd digit exists in the string, return an empty string.<\/li>\n    <\/ul>\n  \n    <h2>Dry Run<\/h2>\n    <p><strong>Input:<\/strong> <code>\"52\"<\/code><\/p>\n    <ol>\n      <li>Start from the end: &#8216;2&#8217; \u2192 even \u2192 skip<\/li>\n      <li>Next: &#8216;5&#8217; \u2192 odd \u2192 return <code>\"5\"<\/code><\/li>\n    <\/ol>\n  \n    <h2>Time &#038; Space Complexity<\/h2>\n    <ul>\n      <li><strong>Time Complexity:<\/strong> O(n), where n is the length of the string<\/li>\n      <li><strong>Space Complexity:<\/strong> O(1), no extra space used<\/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=\"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=\"java\">Java<\/button>\n      <button class=\"wp_blog_code-tab-button\" data-lang=\"py\">Python<\/button>\n    <\/div>\n  \n    <!-- JavaScript -->\n    <div class=\"wp_blog_code-tab-content active\" data-lang=\"js\">\n      <pre><code class=\"language-javascript\">\n  var largestOddNumber = function(s) {\n      let n = s.length - 1;\n      while (n >= 0) {\n          if (Number(s[n]) % 2 == 1) {\n              return s.substring(0, n + 1);\n          }\n          --n;\n      }\n      return \"\";\n  };\n      <\/code><\/pre>\n    <\/div>\n  \n    <!-- C++ -->\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"cpp\">\n      <pre><code class=\"language-cpp\">\n  #include &lt;iostream&gt;\n  using namespace std;\n  \n  string largestOddNumber(string s) {\n      int n = s.length() - 1;\n      while (n >= 0) {\n          if ((s[n] - '0') % 2 == 1) {\n              return s.substr(0, n + 1);\n          }\n          --n;\n      }\n      return \"\";\n  }\n      <\/code><\/pre>\n    <\/div>\n  \n    <!-- C -->\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"c\">\n      <pre><code class=\"language-c\">\n  #include &lt;stdio.h&gt;\n  #include &lt;string.h&gt;\n  \n  void largestOddNumber(char* s, char* result) {\n      int n = strlen(s) - 1;\n      while (n >= 0) {\n          if ((s[n] - '0') % 2 == 1) {\n              strncpy(result, s, n + 1);\n              result[n + 1] = '\\0';\n              return;\n          }\n          --n;\n      }\n      result[0] = '\\0';\n  }\n      <\/code><\/pre>\n    <\/div>\n  \n    <!-- Java -->\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"java\">\n      <pre><code class=\"language-java\">\n  public class Solution {\n      public String largestOddNumber(String s) {\n          int n = s.length() - 1;\n          while (n >= 0) {\n              if ((s.charAt(n) - '0') % 2 == 1) {\n                  return s.substring(0, n + 1);\n              }\n              n--;\n          }\n          return \"\";\n      }\n  }\n      <\/code><\/pre>\n    <\/div>\n  \n    <!-- Python -->\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"py\">\n      <pre><code class=\"language-python\">\n  def largestOddNumber(s: str) -> str:\n      n = len(s) - 1\n      while n >= 0:\n          if int(s[n]) % 2 == 1:\n              return s[:n+1]\n          n -= 1\n      return \"\"\n      <\/code><\/pre>\n    <\/div>\n  <\/div>\n  \n\n\n\n<a href=\"https:\/\/leetcode.com\/problems\/two-sum\/description\/\" target=\"blank\"\n  >Solve this problem.<\/a\n>\n<script>\n  document.addEventListener(\"DOMContentLoaded\", function () {\n    const buttons = document.querySelectorAll(\".wp_blog_code-tab-button\");\n    const contents = document.querySelectorAll(\".wp_blog_code-tab-content\");\n\n    buttons.forEach((button) => {\n      button.addEventListener(\"click\", () => {\n        const lang = button.getAttribute(\"data-lang\");\n\n        buttons.forEach((btn) => btn.classList.remove(\"active\"));\n        button.classList.add(\"active\");\n\n        contents.forEach((content) => {\n          content.classList.toggle(\n            \"active\",\n            content.getAttribute(\"data-lang\") === lang\n          );\n        });\n      });\n    });\n  });\n<\/script>\n\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The task is to find the largest-valued odd number that can be formed from a given numeric string by removing trailing even digits. The number must be a substring starting from index 0 to some valid index. Steps Start from the end of the string and move backward. Check if the current digit is odd<\/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":[322,176,175,174,172,173],"tags":[],"class_list":["post-7480","post","type-post","status-publish","format-standard","category-algorithms-and-data-structures","category-csharp","category-cplusplus","category-java","category-javascript","category-python"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7480","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=7480"}],"version-history":[{"count":1,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7480\/revisions"}],"predecessor-version":[{"id":7493,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7480\/revisions\/7493"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=7480"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=7480"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=7480"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}