{"id":12210,"date":"2026-04-15T23:48:36","date_gmt":"2026-04-15T18:18:36","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=12210"},"modified":"2026-04-16T00:10:32","modified_gmt":"2026-04-15T18:40:32","slug":"reorganize-string","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/reorganize-string\/","title":{"rendered":"Reorganize String"},"content":{"rendered":"\n\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<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    <h1 class=\"wp_blog_main-heading\"><\/h1>\n    <div class=\"wp_blog_explanation\">\n        <h2>Problem Statement:<\/h2>\n        <p>\n            Given a string <code>s<\/code>, rearrange the characters of <code>s<\/code> so that any two adjacent characters are not the same.\n        <\/p>\n        <p>\n            Return <i>any possible rearrangement of <code>s<\/code> or return <code>\"\"<\/code> if not possible<\/i>.\n        <\/p>\n\n                <h2>Examples:<\/h2>\n\n                <h3>Example 1:<\/h3>\n                <p><strong>Input:<\/strong> s = &#8220;aab&#8221;\n                <\/p>\n                <p><strong>Output:<\/strong> &#8220;aba&#8221;<\/p>\n\n                <h3>Example 2:<\/h3>\n                <p><strong>Input:<\/strong> s = &#8220;aaab&#8221;<\/p>\n\n                <p><strong>Output:<\/strong> &#8220;&#8221;<\/p>\n\n                <!-- <h3>Example 3:<\/h3>\n                <p><strong>Input:<\/strong> s = \"2[abc]3[cd]ef\"<\/p>\n\n                <p><strong>Output:<\/strong> \"abcabccdcdcdef\"<\/p> \n\n                <h5>Example 3:<\/h5>\n                <p><strong>Input:<\/strong>\n                <\/p>\n                <p>\n                    nums1 = [0], m = 0\n                    nums2 = [1], n = 1\n                <\/p>    \n                <p><strong>Output:<\/strong>[1]<\/p>\n                  <p>\n                  <code>Explanation:<\/code>\n                 The arrays we are merging are [] and [1].\n                    The result of the merge is [1].\n                    Note that because m = 0, there are no elements in nums1. \n                    The 0 is only there to ensure the merge result can fit in nums1.\n                <\/p> -->\n\n                <h2>Constraints<\/h2>\n                <p><code>1 <= s.length <= 500<\/code><\/p>\n                <p><code>s<\/code> consists of lowercase English letters.<\/p>\n\n                    <h2>Time Complexity:<\/h2>\n                    <li>\n                      <p><strong>Time Complexity = O(n + k log k ) \u2248 O(n)<\/strong>\n                        where <code>m<\/code> is length of the generated string at each step.\n                      <\/li>\n                    <h2>Space Complexity:<\/h2>\n                    <li>\n                      <p><strong>Space Complexity = O(n)<\/strong><\/p>\n                    <\/li>\n\n<h2>Approach<\/h2>\n<ul>\n    <li>First, <code>count the frequency of each character<\/code> in the string and track the <strong>maximum frequency<\/strong>.<\/li>\n    <li>\n    If any <strong>character appears more than \u2308n\/2\u2309 times<\/strong>, it is impossible to rearrange the string without <code>adjacent duplicates<\/code>, so return an empty string.\n    <\/li>\n    \n    <li> Sort the <code>characters in descending order<\/code> based on their frequency so that the most <strong>frequent characters<\/strong> are placed first. <\/li>\n\n    <li>\n        Create a <strong>result array and start filling characters<\/strong> at even <code>indices (0, 2, 4, \u2026)<\/code>. Once even positions are <strong>filled<\/strong>, continue filling at odd <code>indices (1, 3, 5, \u2026)<\/code>.\n    <\/li>\n    <li>This <strong>placement ensures<\/strong> that the same characters are spaced apart, preventing <code>adjacent duplicates<\/code>.<\/li>\n    <li>Finally, join the <strong>array to form the reorganized string<\/strong>.<\/li>\n<\/ul>\n\n\n<h2>Dry Run<\/h2>\n<div style=\"background: var(--light-bg); border-left: 4px solid var(--primary); padding: 1rem; border-radius: var(--tab-radius); margin: 1rem 0; color: var(--text-dark);\"> \n  <p><strong>Input:<\/strong> <code>s = \"aab\"<\/code><\/p> \n  \n  <pre style=\"white-space: pre-wrap; background: var(--code-bg); padding: 1rem; border-radius: 8px; overflow-x: auto; color: var(--code-text);\">\nInitial:\n   freq = {}\n   maxFreq = 0\n\nCounting frequency:\n   c = 'a' \u2192 freq['a'] = 1, maxFreq = 1\n   c = 'a' \u2192 freq['a'] = 2, maxFreq = 2\n   c = 'b' \u2192 freq['b'] = 1, maxFreq = 2\n\n   freq = { a: 2, b: 1 }\n   n = 3\n\nCheck impossible case:\n   maxFreq = 2, ceil(3\/2) = 2 \u2192 valid\n\nSort characters:\n   chars = ['a', 'b']  (sorted by frequency desc)\n\nInitialize:\n   result = [ , , ]\n   i = 0\n\nFill characters:\n\n   ch = 'a', count = 2\n\n      count = 2:\n         i = 0 \u2192 result[0] = 'a'\n         i = 2\n         count = 1\n\n      count = 1:\n         i = 2 \u2192 result[2] = 'a'\n         i = 4\n         count = 0\n\n   result = ['a', , 'a']\n\n   ch = 'b', count = 1\n\n      count = 1:\n         i = 4 >= n \u2192 i = 1\n         result[1] = 'b'\n         i = 3\n         count = 0\n\n   result = ['a', 'b', 'a']\n\nFinal:\n   return \"aba\"\n  <\/pre> \n  \n  <p><strong>Output:<\/strong> <code>\"aba\"<\/code><\/p> \n<\/div>\n<\/div>\n\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\">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 reorganizeString = function(s) {\n    let freq = {};\n    let maxFreq = 0;\n\n    \/\/ Count frequency\n    for (let c of s) {\n        freq[c] = (freq[c] || 0) + 1;\n        maxFreq = Math.max(maxFreq, freq[c]);\n    }\n\n    let n = s.length;\n\n    \/\/ Impossible case\n    if (maxFreq > Math.ceil(n \/ 2)) {\n        return \"\";\n    }\n\n    \/\/ Sort characters by frequency (descending)\n    let chars = Object.keys(freq).sort((a, b) => freq[b] - freq[a]);\n\n    let result = new Array(n);\n    let i = 0;\n\n    \/\/ Fill even indices first, then odd\n    for (let ch of chars) {\n        let count = freq[ch];\n\n        while (count > 0) {\n            if (i >= n) {\n                i = 1; \/\/ move to odd index\n            }\n\n            result[i] = ch;\n            i += 2;\n            count--;\n        }\n    }\n\n    return result.join(\"\");\n};\n    <\/code><\/pre>\n    <\/div>\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"py\">\n        <pre><code class=\"language-python\">\ndef reorganizeString(s):\n    freq = {}\n    maxFreq = 0\n\n    # Count frequency\n    for c in s:\n        freq[c] = freq.get(c, 0) + 1\n        maxFreq = max(maxFreq, freq[c])\n\n    n = len(s)\n\n    # Impossible case\n    if maxFreq > (n + 1) \/\/ 2:\n        return \"\"\n\n    # Sort characters by frequency (descending)\n    chars = sorted(freq.keys(), key=lambda x: -freq[x])\n\n    result = [\"\"] * n\n    i = 0\n\n    # Fill even indices first, then odd\n    for ch in chars:\n        count = freq[ch]\n\n        while count > 0:\n            if i >= n:\n                i = 1\n\n            result[i] = ch\n            i += 2\n            count -= 1\n\n    return \"\".join(result)\n    <\/code><\/pre>\n    <\/div>\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"java\">\n        <pre><code class=\"language-java\">\nimport java.util.*;\n\nclass Solution {\n    public String reorganizeString(String s) {\n        HashMap<Character, Integer> freq = new HashMap<>();\n        int maxFreq = 0;\n\n        \/\/ Count frequency\n        for (char c : s.toCharArray()) {\n            freq.put(c, freq.getOrDefault(c, 0) + 1);\n            maxFreq = Math.max(maxFreq, freq.get(c));\n        }\n\n        int n = s.length();\n\n        \/\/ Impossible case\n        if (maxFreq > (n + 1) \/ 2) {\n            return \"\";\n        }\n\n        \/\/ Sort characters by frequency\n        List<Character> chars = new ArrayList<>(freq.keySet());\n        chars.sort((a, b) -> freq.get(b) - freq.get(a));\n\n        char[] result = new char[n];\n        int i = 0;\n\n        \/\/ Fill even indices first, then odd\n        for (char ch : chars) {\n            int count = freq.get(ch);\n\n            while (count > 0) {\n                if (i >= n) {\n                    i = 1;\n                }\n                result[i] = ch;\n                i += 2;\n                count--;\n            }\n        }\n\n        return new String(result);\n    }\n}\n<\/code><\/pre>\n    <\/div>\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"cpp\">\n        <pre><code class=\"language-cpp\">\n#include &lt;bits\/stdc++.h&gt;\nusing namespace std;\n\nstring reorganizeString(string s) {\n    unordered_map<char, int> freq;\n    int maxFreq = 0;\n\n    \/\/ Count frequency\n    for (char c : s) {\n        freq[c]++;\n        maxFreq = max(maxFreq, freq[c]);\n    }\n\n    int n = s.length();\n\n    \/\/ Impossible case\n    if (maxFreq > (n + 1) \/ 2) {\n        return \"\";\n    }\n\n    \/\/ Sort characters by frequency\n    vector<char> chars;\n    for (auto &p : freq) {\n        chars.push_back(p.first);\n    }\n\n    sort(chars.begin(), chars.end(), [&](char a, char b) {\n        return freq[a] > freq[b];\n    });\n\n    vector<char> result(n);\n    int i = 0;\n\n    \/\/ Fill even indices first, then odd\n    for (char ch : chars) {\n        int count = freq[ch];\n\n        while (count--) {\n            if (i >= n) {\n                i = 1;\n            }\n            result[i] = ch;\n            i += 2;\n        }\n    }\n\n    return string(result.begin(), result.end());\n}\n    <\/code><\/pre>\n    <\/div>\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;stdlib.h&gt;\n#include &lt;string.h&gt;\n\n#define MAX 256\n\nint compare(const void *a, const void *b, void *freq) {\n    int *f = (int *)freq;\n    return f[*(char*)b] - f[*(char*)a];\n}\n\nchar* reorganizeString(char* s) {\n    int freq[MAX] = {0};\n    int n = strlen(s);\n    int maxFreq = 0;\n\n    \/\/ Count frequency\n    for (int i = 0; i < n; i++) {\n        freq[(int)s[i]]++;\n        if (freq[(int)s[i]] > maxFreq)\n            maxFreq = freq[(int)s[i]];\n    }\n\n    \/\/ Impossible case\n    if (maxFreq > (n + 1) \/ 2) {\n        char* empty = malloc(1);\n        empty[0] = '\\0';\n        return empty;\n    }\n\n    char chars[MAX];\n    int idx = 0;\n\n    for (int i = 0; i < MAX; i++) {\n        if (freq[i] > 0) {\n            chars[idx++] = (char)i;\n        }\n    }\n\n    \/\/ Sort chars by frequency (simple bubble sort for clarity)\n    for (int i = 0; i < idx; i++) {\n        for (int j = i + 1; j < idx; j++) {\n            if (freq[(int)chars[j]] > freq[(int)chars[i]]) {\n                char temp = chars[i];\n                chars[i] = chars[j];\n                chars[j] = temp;\n            }\n        }\n    }\n\n    char* result = (char*)malloc(n + 1);\n    int pos = 0;\n\n    for (int k = 0; k < idx; k++) {\n        int count = freq[(int)chars[k]];\n\n        while (count--) {\n            if (pos >= n) {\n                pos = 1;\n            }\n            result[pos] = chars[k];\n            pos += 2;\n        }\n    }\n\n    result[n] = '\\0';\n    return result;\n}\n   <\/code><\/pre>\n    <\/div>\n    <div class=\"wp_blog_code-tab-content\" data-lang=\"cs\">\n        <pre><code class=\"language-csharp\">\nusing System;\nusing System.Collections.Generic;\nusing System.Linq;\n\npublic class Solution {\n    public string ReorganizeString(string s) {\n        Dictionary<char, int> freq = new Dictionary<char, int>();\n        int maxFreq = 0;\n\n        \/\/ Count frequency\n        foreach (char c in s) {\n            if (!freq.ContainsKey(c))\n                freq[c] = 0;\n            freq[c]++;\n            maxFreq = Math.Max(maxFreq, freq[c]);\n        }\n\n        int n = s.Length;\n\n        \/\/ Impossible case\n        if (maxFreq > (n + 1) \/ 2) {\n            return \"\";\n        }\n\n        \/\/ Sort characters\n        var chars = freq.Keys.OrderByDescending(c => freq[c]).ToList();\n\n        char[] result = new char[n];\n        int i = 0;\n\n        \/\/ Fill even indices first, then odd\n        foreach (char ch in chars) {\n            int count = freq[ch];\n\n            while (count > 0) {\n                if (i >= n) {\n                    i = 1;\n                }\n                result[i] = ch;\n                i += 2;\n                count--;\n            }\n        }\n\n        return new string(result);\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\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ud83c\udf19 Problem Statement: Given a string s, rearrange the characters of s so that any two adjacent characters are not the same. Return any possible rearrangement of s or return &#8220;&#8221; if not possible. Examples: Example 1: Input: s = &#8220;aab&#8221; Output: &#8220;aba&#8221; Example 2: Input: s = &#8220;aaab&#8221; Output: &#8220;&#8221; Constraints 1 Math.ceil(n \/<\/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":[210,322,176,175,211,811,174,172,173],"tags":[],"class_list":["post-12210","post","type-post","status-publish","format-standard","category-algorithms","category-algorithms-and-data-structures","category-csharp","category-cplusplus","category-data-structures","category-data-structures-and-algorithms","category-java","category-javascript","category-python"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/12210","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=12210"}],"version-history":[{"count":1,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/12210\/revisions"}],"predecessor-version":[{"id":12211,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/12210\/revisions\/12211"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=12210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=12210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=12210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}