{"id":7129,"date":"2025-06-21T13:12:36","date_gmt":"2025-06-21T07:42:36","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=7129"},"modified":"2025-10-22T19:57:05","modified_gmt":"2025-10-22T14:27:05","slug":"reversedigits","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/reversedigits\/","title":{"rendered":"Reverse Digits of an Integer"},"content":{"rendered":"\n<!-- PrismJS for Syntax Highlighting -->\n<link\n    href=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/themes\/prism-tomorrow.min.css\"\n    rel=\"stylesheet\"\n\/>\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\n<style>\n.wp_blog_theme {\n  --primary: #E58C32;\n  --secondary: #030302;\n  --light-bg: #fef9f4;\n  --text-dark: #2d2d2d;\n  --tab-radius: 12px;\n  --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);\n  --code-bg: #001f3f;\n  --code-text: #d4f1ff;\n}\n\n.wp_blog_container {\n  font-family: 'Segoe UI', sans-serif;\n  background: var(--light-bg);\n  margin: 0;\n  padding: 0;\n  color: var(--text-dark);\n}\n\n\/* Heading *\/\n.wp_blog_main-heading {\n  text-align: center;\n  font-size: 2.4rem;\n  color: var(--primary);\n  margin-top: 2.5rem;\n  font-weight: bold;\n}\n\n\/* Explanation Card *\/\n.wp_blog_explanation,\n.wp_blog_code-tabs-container {\n  max-width: 940px;\n  margin: 2rem auto;\n  padding: 2rem;\n  background: white;\n  border-radius: var(--tab-radius);\n  box-shadow: var(--shadow);\n}\n\n\/* Text and Visuals *\/\n.wp_blog_explanation h2 {\n  font-size: 1.4rem;\n  color: var(--primary);\n  margin-bottom: 0.5rem;\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}\n\n.wp_blog_explanation code {\n  background: #fef9f4; 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\/* makes it the reference for absolute children *\/\n}\n\n.wp_blog_toggle-btn {\n  position: absolute;\n  top: 1rem;\n  right: 1rem;\n  z-index: 9999;\n  padding: 0.5rem 0.8rem;\n  border-radius: 10%;\n  background: var(--primary);\n  color: white;\n  font-weight: bold;\n  cursor: pointer;\n  border: none;\n  box-shadow: var(--shadow);\n  transition: background 0.3s, transform 0.2s;\n}\n\n.wp_blog_toggle-btn:hover {\n  background: #cc772e;\n}\n\n.wp_blog_theme.dark-mode .wp_blog_code-tabs-container {\n  background: #1e1e1e;\n}\n<\/style>\n\n<div class=\"wp_blog_container wp_blog_theme\">\n                <button id=\"blogNotesThemeToggle\" class=\"wp_blog_toggle-btn\">\ud83c\udf19<\/button>\n\n    <h1 class=\"wp_blog_main-heading\"><\/h1>\n\n    <div class=\"wp_blog_explanation\">\n        <h2>Problem Statement:<\/h2>\n        <p>\n            Write a function <code>reverse(x)<\/code> that takes a\n            <code>32-bit<\/code> signed integer and returns its digits reversed.\n            If the reversed value overflows the 32-bit signed integer range,\n            <code>return 0<\/code>.\n        <\/p>\n\n        <h2>Requirements:<\/h2>\n        <ul>\n            <li>Reverse the digits of a <code>32-bit<\/code> signed integer.<\/li>\n            <li>Return <code>0<\/code>if the result overflows.<\/li>\n        <\/ul>\n\n        <h2>Constraints:<\/h2>\n        <p>\n            <code>Time Complexity: O(d)<\/code>Where <code>d<\/code>is the numberof digits.\n\n            <p><code>Space Complexity: O(1)<\/code> \u2014 Constant space.<\/p>\n        <\/p>\n\n\n        <h2>Example:<\/h2>\n        <p><strong>Input:<\/strong><code>123<\/code><\/p>\n        <p><strong>Output:<\/strong><code>321<\/code><\/p>\n        \n        <p><strong>Input:<\/strong><code>-123<\/code><\/p>\n        <p><strong>Output:<\/strong><code>-321<\/code><\/p>\n\n        <p><strong>Input:<\/strong><code>1534236469<\/code><\/p>\n        <p><strong>Output:<\/strong><code>0 (overflow)<\/code><\/p>\n\n        <h2>Approach:<\/h2>\n        <ul>\n            <li>\n                <strong>Preserve the Original:<\/strong> Save<code>x<\/code>in<code>xCopy<\/code>.<\/li>\n\n                <li>\n                    <strong>Work with Absolute Value:<\/strong> Use<code>Math.abs(x)<\/code>or<code>abs(x)<\/code>to simplify reversal.\n                <\/li>\n                <li>\n                    <strong>Reverse Digits:<\/strong> Intialize<code>rev = 0<\/code>.While<code>x != 0 :\n                        last = x % 10\n                        rev = rev * 10 + last\n                        x \/\/= 10\n                    <\/code>\n                <\/li>\n\n                <li>\n                    <strong>Check for Overflow:<\/strong> Return<code>0<\/code>if reversed number is outside<code>32-bit<\/code>int range.\n                <\/li>\n\n                <li>\n                    <strong>Restore Sign:<\/strong> Return<code>-rev<\/code>if <code>xCopy < 0<\/code>, else <code>rev<\/code>.\n                <\/li>\n        <\/ul>\n\n        <h2>Visualisation:<\/h2>\n        <img decoding=\"async\"\n            src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-26-at-10.13.39\u202fPM.png\"\n            alt=\"Visual representation of reverse digit\"\n        \/>\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\">\n                JavaScript\n            <\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"py\">\n                Python\n            <\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"java\">\n                Java\n            <\/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        <!-- JavaScript -->\n        <div class=\"wp_blog_code-tab-content active\" data-lang=\"js\">\n            <pre><code class=\"language-javascript\">\nvar reverse = function(x) {\n  let xCopy = x;\n  x = Math.abs(x);\n  let rev = 0;\n  while (x > 0) {\n    let last = x % 10;\n    rev = rev * 10 + last;\n    x = Math.floor(x \/ 10);\n  }\n  if (rev > 2**31 - 1) return 0;\n  return xCopy < 0 ? -rev : rev;\n};\n\nconsole.log(reverse(123)); \/\/ 321\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\">\nclass Solution(object):\n    def reverse(self, x):\n        rev = 0\n        n = abs(x)\n        while n != 0:\n            last = n % 10\n            rev = rev * 10 + last\n            n \/\/= 10\n        if rev > 2**31 - 1:\n            return 0\n        return -rev if x < 0 else rev\n\nsol = Solution()\nprint(sol.reverse(123))  # Output: 321\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\">\npublic class Solution {\n  public int reverse(int x) {\n    long rev = 0;\n    int n = Math.abs(x);\n    while (n != 0) {\n      int last = n % 10;\n      rev = rev * 10 + last;\n      n \/= 10;\n    }\n    if (rev > Integer.MAX_VALUE) return 0;\n    return x < 0 ? (int)-rev : (int)rev;\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\">\nclass Solution {\npublic:\n  int reverse(int x) {\n    long long rev = 0;\n    long long n = x;\n    while (n != 0) {\n      int last = n % 10;\n      rev = rev * 10 + last;\n      n \/= 10;\n    }\n    if (rev > INT_MAX || rev < INT_MIN) return 0;\n    return (int)rev;\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;limits.h&gt;\n\nint reverse(int x) {\n  long long rev = 0;\n  long long n = x;\n  while (n != 0) {\n    int last = n % 10;\n    rev = rev * 10 + last;\n    n \/= 10;\n  }\n  if (rev > INT_MAX || rev < INT_MIN) return 0;\n  return (int)rev;\n}<\/code><\/pre>\n        <\/div>\n\n        <!-- C# -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"cs\">\n            <pre><code class=\"language-csharp\">\nusing System;\nclass Program {\n static int ReverseInteger(int x) {\n    int result = 0;\n    while (x != 0) {\n     int digit = x % 10;\n     x \/= 10;\n        if (result > int.MaxValue \/ 10 || (result == int.MaxValue \/ 10 && digit > 7)) {\n          return 0;\n        }\n        if (result < int.MinValue \/ 10 || (result == int.MinValue \/ 10 &#038;&#038; digit < -8)) {\n          return 0;\n        }\n        result = result * 10 + digit;\n    }\n    return result;\n}\nstatic void Main() {\n int input = 123;\n Console.WriteLine(\"Reversed: \" + ReverseInteger(input)); \/\/ Output: 321\n input = -120;\n Console.WriteLine(\"Reversed: \" + ReverseInteger(input)); \/\/ Output: -21\n input = 1534236469;\n Console.WriteLine(\"Reversed: \" + ReverseInteger(input)); \/\/ Output: 0 (overflow)\n }\n}\n            <\/code><\/pre>\n        <\/div>\n    <\/div>\n<\/div>\n\n<script>\ndocument.addEventListener(\"DOMContentLoaded\", () => {\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      contents.forEach((content) => content.classList.remove(\"active\"));\n\n      button.classList.add(\"active\");\n      document\n        .querySelector(`.wp_blog_code-tab-content[data-lang=\"${lang}\"]`)\n        .classList.add(\"active\");\n    });\n  });\n\n  const themeToggle = document.getElementById(\"blogNotesThemeToggle\");\n  const themeContainer = document.querySelector(\".wp_blog_theme\");\n\n  themeToggle.addEventListener(\"click\", () => {\n    themeContainer.classList.toggle(\"dark-mode\");\n    themeToggle.textContent =\n      themeContainer.classList.contains(\"dark-mode\") ? \"\u2600\ufe0f\" : \"\ud83c\udf19\";\n  });\n});\n<\/script>\n\n","protected":false},"excerpt":{"rendered":"<p>\ud83c\udf19 Problem Statement: Write a function reverse(x) that takes a 32-bit signed integer and returns its digits reversed. If the reversed value overflows the 32-bit signed integer range, return 0. Requirements: Reverse the digits of a 32-bit signed integer. Return 0if the result overflows. Constraints: Time Complexity: O(d)Where dis the numberof digits. Space Complexity: O(1)<\/p>\n","protected":false},"author":108,"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":[210,322,260,176,175,211,811,810,174,172,173],"tags":[],"class_list":["post-7129","post","type-post","status-publish","format-standard","category-algorithms","category-algorithms-and-data-structures","category-c-c-plus-plus","category-csharp","category-cplusplus","category-data-structures","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\/7129","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\/108"}],"replies":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/comments?post=7129"}],"version-history":[{"count":4,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7129\/revisions"}],"predecessor-version":[{"id":10538,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/7129\/revisions\/10538"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=7129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=7129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=7129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}