{"id":5939,"date":"2019-12-08T02:00:16","date_gmt":"2019-12-08T10:00:16","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=5939"},"modified":"2019-12-08T02:00:51","modified_gmt":"2019-12-08T10:00:51","slug":"leetcode-1282-group-the-people-given-the-group-size-they-belong-to","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/hashtable\/leetcode-1282-group-the-people-given-the-group-size-they-belong-to\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 1282. Group the People Given the Group Size They Belong To"},"content":{"rendered":"\n

There are n<\/code> people whose IDs<\/strong> go from 0<\/code> to n - 1<\/code> and each person belongs exactly<\/strong> to one group. Given the array groupSizes<\/code> of length n<\/code> telling the group size each person belongs to, return the groups there are and the people’s IDs<\/strong> each group includes.<\/p>\n\n\n\n

You can return any solution in any order and the same applies for IDs. Also, it is guaranteed that there exists at least one solution. <\/p>\n\n\n\n

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

Input:<\/strong> groupSizes = [3,3,3,3,3,1,3]\nOutput:<\/strong> [[5],[0,1,2],[3,4,6]]\nExplanation:<\/strong> \nOther possible solutions are [[2,1,6],[5],[0,4,3]] and [[5],[0,6,2],[4,3,1]].\n<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input:<\/strong> groupSizes = [2,1,3,3,3,2]\nOutput:<\/strong> [[1],[0,5],[2,3,4]]\n<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n
  • groupSizes.length == n<\/code><\/li>
  • 1 <= n <= 500<\/code><\/li>
  • 1 <= groupSizes[i] <= n<\/code><\/li><\/ul>\n\n\n\n
    Solution: HashMap + Greedy<\/strong><\/h2>\n\n\n\n
    hashmap: group_size -> {ids}
    greedy: whenever a group of size s has s people, assign those s people to the same group.<\/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> groupThePeople(vector& groupSizes) {\n    vector> ans;\n    const int n =  groupSizes.size();\n    unordered_map> m;\n    for (int i = 0; i < n; ++i) {\n      auto& v = m[groupSizes[i]];\n      v.push_back(i);\n      if (v.size() == groupSizes[i])\n        ans.push_back(std::move(v));                       \n    }\n    return ans;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    There are n people whose IDs go from 0 to n – 1 and each person belongs exactly to one group. Given the array groupSizes of length n telling the group size each person belongs to, return the groups there…<\/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":[88,306,82,177],"class_list":["post-5939","post","type-post","status-publish","format-standard","hentry","category-hashtable","tag-greedy","tag-group","tag-hashtable","tag-medium","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/5939","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=5939"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/5939\/revisions"}],"predecessor-version":[{"id":5941,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/5939\/revisions\/5941"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=5939"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=5939"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=5939"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}