{"id":9474,"date":"2022-02-04T17:13:01","date_gmt":"2022-02-05T01:13:01","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=9474"},"modified":"2022-02-04T17:13:19","modified_gmt":"2022-02-05T01:13:19","slug":"leetcode-2150-find-all-lonely-numbers-in-the-array","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/hashtable\/leetcode-2150-find-all-lonely-numbers-in-the-array\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 2150. Find All Lonely Numbers in the Array"},"content":{"rendered":"\n

You are given an integer array nums<\/code>. A number x<\/code> is lonely<\/strong> when it appears only once<\/strong>, and no adjacent<\/strong> numbers (i.e. x + 1<\/code> and x - 1)<\/code> appear in the array.<\/p>\n\n\n\n

Return all<\/strong> lonely numbers in <\/em>nums<\/code>. You may return the answer in any order<\/strong>.<\/p>\n\n\n\n

Example 1:<\/strong><\/p>\n\n\n\n

Input:<\/strong> nums = [10,6,5,8]\nOutput:<\/strong> [10,8]\nExplanation:<\/strong> \n- 10 is a lonely number since it appears exactly once and 9 and 11 does not appear in nums.\n- 8 is a lonely number since it appears exactly once and 7 and 9 does not appear in nums.\n- 5 is not a lonely number since 6 appears in nums and vice versa.\nHence, the lonely numbers in nums are [10, 8].\nNote that [8, 10] may also be returned.\n<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input:<\/strong> nums = [1,3,5,3]\nOutput:<\/strong> [1,5]\nExplanation:<\/strong> \n- 1 is a lonely number since it appears exactly once and 0 and 2 does not appear in nums.\n- 5 is a lonely number since it appears exactly once and 4 and 6 does not appear in nums.\n- 3 is not a lonely number since it appears twice.\nHence, the lonely numbers in nums are [1, 5].\nNote that [5, 1] may also be returned.\n<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n
  • 1 <= nums.length <= 105<\/sup><\/code><\/li>
  • 0 <= nums[i] <= 106<\/sup><\/code><\/li><\/ul>\n\n\n\n
    Solution: Counter<\/strong><\/h2>\n\n\n\n
    Computer the frequency of each number in the array, for a given number x with freq = 1, check freq of (x – 1) and (x + 1), if both of them are zero then x is lonely.<\/p>\n\n\n\n
    Time complexity: O(n)
    Space complexity: O(n)<\/p>\n\n\n\n
    \n
    C++<\/h2>\n
    \n\n
    \n\/\/ Author: Huahua\nclass Solution {\npublic:\n  vector findLonely(vector& nums) {\n    unordered_map m;\n    for (int x : nums)\n      ++m[x];\n    vector ans;\n    for (const auto [x, c] : m)\n      if (c == 1 && !m.count(x + 1) && !m.count(x - 1))\n        ans.push_back(x);\n    return ans;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    You are given an integer array nums. A number x is lonely when it appears only once, and no adjacent numbers (i.e. x + 1 and x – 1) appear in the array. Return all lonely numbers in nums. You…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[70],"tags":[254,82,177],"class_list":["post-9474","post","type-post","status-publish","format-standard","hentry","category-hashtable","tag-counter","tag-hashtable","tag-medium","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9474","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=9474"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9474\/revisions"}],"predecessor-version":[{"id":9476,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9474\/revisions\/9476"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=9474"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=9474"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=9474"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}