{"id":2931,"date":"2018-06-26T21:04:48","date_gmt":"2018-06-27T04:04:48","guid":{"rendered":"http:\/\/zxi.mytechroad.com\/blog\/?p=2931"},"modified":"2018-06-26T21:07:21","modified_gmt":"2018-06-27T04:07:21","slug":"leetcode-859-buddy-strings","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/string\/leetcode-859-buddy-strings\/","title":{"rendered":"\u82b1\u8bdd\u9171 LeetCode 859. Buddy Strings"},"content":{"rendered":"<h1><strong>Problem<\/strong><\/h1>\n<p>Given two strings\u00a0<code>A<\/code>\u00a0and\u00a0<code>B<\/code>\u00a0of lowercase letters, return\u00a0<code>true<\/code>\u00a0if and only if we\u00a0can swap two letters in\u00a0<code>A<\/code>\u00a0so that the result equals\u00a0<code>B<\/code>.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Example 1:<\/strong><\/p>\n<div>\n<pre class=\"crayon:false\"><strong>Input: <\/strong>A = <span id=\"example-input-1-1\">\"ab\"<\/span>, B = <span id=\"example-input-1-2\">\"ba\"<\/span>\r\n<strong>Output: <\/strong><span id=\"example-output-1\">true<\/span>\r\n<\/pre>\n<div>\n<p><strong>Example 2:<\/strong><\/p>\n<pre class=\"crayon:false\"><strong>Input: <\/strong>A = <span id=\"example-input-2-1\">\"ab\"<\/span>, B = <span id=\"example-input-2-2\">\"ab\"<\/span>\r\n<strong>Output: <\/strong><span id=\"example-output-2\">false<\/span>\r\n<\/pre>\n<div>\n<p><strong>Example 3:<\/strong><\/p>\n<pre class=\"crayon:false\"><strong>Input: <\/strong>A = <span id=\"example-input-3-1\">\"aa\"<\/span>, B = <span id=\"example-input-3-2\">\"aa\"<\/span>\r\n<strong>Output: <\/strong><span id=\"example-output-3\">true<\/span>\r\n<\/pre>\n<div>\n<p><strong>Example 4:<\/strong><\/p>\n<pre class=\"crayon:false\"><strong>Input: <\/strong>A = <span id=\"example-input-4-1\">\"aaaaaaabc\"<\/span>, B = <span id=\"example-input-4-2\">\"aaaaaaacb\"<\/span>\r\n<strong>Output: <\/strong><span id=\"example-output-4\">true<\/span>\r\n<\/pre>\n<div>\n<p><strong>Example 5:<\/strong><\/p>\n<pre class=\"crayon:false\"><strong>Input: <\/strong>A = <span id=\"example-input-5-1\">\"\"<\/span>, B = <span id=\"example-input-5-2\">\"aa\"<\/span>\r\n<strong>Output: <\/strong><span id=\"example-output-5\">false<\/span>\r\n<\/pre>\n<p><strong>Note:<\/strong><\/p>\n<ol>\n<li><code>0 &lt;= A.length &lt;= 20000<\/code><\/li>\n<li><code>0 &lt;= B.length &lt;= 20000<\/code><\/li>\n<li><code>A<\/code>\u00a0and\u00a0<code>B<\/code>\u00a0consist only of lowercase letters.<\/li>\n<\/ol>\n<h1><strong>Solution: HashTable<\/strong><\/h1>\n<p>Time complexity: O(n)<\/p>\n<p>Space complexity: O(26)<\/p>\n<pre class=\"lang:c++ decode:true \">\/\/ Author: Huahua\r\n\/\/ Running time: 7 ms\r\nclass Solution {\r\npublic:\r\n  bool buddyStrings(string A, string B) {\r\n    if (A.length() != B.length()) return false;\r\n    vector&lt;int&gt; ca(26);\r\n    vector&lt;int&gt; cb(26);\r\n    int diff = 0;\r\n    for (int i = 0; i &lt; A.length(); ++i) {\r\n      if (A[i] != B[i] &amp;&amp; diff++ &gt; 2) return false;\r\n      ++ca[A[i]-'a'];\r\n      ++cb[B[i]-'a'];\r\n    }\r\n    for (int i = 0; i &lt; 26; ++i) {\r\n      if (diff == 0 &amp;&amp; ca[i] &gt; 1) return true;\r\n      if (ca[i] != cb[i]) return false;\r\n    }\r\n    return diff == 2;\r\n  }\r\n};<\/pre>\n<p>&nbsp;<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Problem Given two strings\u00a0A\u00a0and\u00a0B\u00a0of lowercase letters, return\u00a0true\u00a0if and only if we\u00a0can swap two letters in\u00a0A\u00a0so that the result equals\u00a0B. &nbsp; Example 1: Input: A =&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[70,47],"tags":[222,82,4],"class_list":["post-2931","post","type-post","status-publish","format-standard","hentry","category-hashtable","category-string","tag-easy","tag-hashtable","tag-string","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/2931","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/comments?post=2931"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/2931\/revisions"}],"predecessor-version":[{"id":2933,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/2931\/revisions\/2933"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=2931"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=2931"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=2931"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}