{"id":3634,"date":"2018-08-19T20:05:37","date_gmt":"2018-08-20T03:05:37","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=3634"},"modified":"2018-08-19T20:05:46","modified_gmt":"2018-08-20T03:05:46","slug":"leetcode-888-fair-candy-swap","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/hashtable\/leetcode-888-fair-candy-swap\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 888. Fair Candy Swap"},"content":{"rendered":"

Problem<\/strong><\/h1>\n

Alice and Bob have candy bars of different sizes:\u00a0A[i]<\/code>\u00a0is the size of the\u00a0i<\/code>-th bar of candy that Alice has, and\u00a0B[j]<\/code>\u00a0is the size of the\u00a0j<\/code>-th bar of candy that Bob has.<\/p>\n

Since they are friends, they would like to exchange one candy bar each so that after the exchange, they both have the same total\u00a0amount of candy.\u00a0 (The total amount of candy\u00a0a person has is the sum of the sizes of candy\u00a0bars they have.<\/em>)<\/p>\n

Return an integer array\u00a0ans<\/code>\u00a0where\u00a0ans[0]<\/code>\u00a0is the size of the candy bar that Alice must exchange, and\u00a0ans[1]<\/code>\u00a0is the size of the candy bar that Bob must exchange.<\/p>\n

If there are multiple answers, you may return any one of them.\u00a0 It is guaranteed an answer exists.<\/p>\n

\n

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

Input: <\/strong>A = [1,1]<\/span>, B = [2,2]<\/span>\r\nOutput: <\/strong>[1,2]<\/span>\r\n<\/pre>\n
\n
Example 2:<\/strong><\/p>\n
Input: <\/strong>A = [1,2]<\/span>, B = [2,3]<\/span>\r\nOutput: <\/strong>[1,2]<\/span>\r\n<\/pre>\n
\n
Example 3:<\/strong><\/p>\n
Input: <\/strong>A = [2]<\/span>, B = [1,3]<\/span>\r\nOutput: <\/strong>[2,3]<\/span>\r\n<\/pre>\n
\n
Example 4:<\/strong><\/p>\n
Input: <\/strong>A = [1,2,5]<\/span>, B = [2,4]<\/span>\r\nOutput: <\/strong>[5,4]<\/span>\r\n<\/pre>\n
Note:<\/strong><\/p>\n
    \n
  • 1 <= A.length <= 10000<\/code><\/li>\n
  • 1 <= B.length <= 10000<\/code><\/li>\n
  • 1 <= A[i] <= 100000<\/code><\/li>\n
  • 1 <= B[i] <= 100000<\/code><\/li>\n
  • It is guaranteed that Alice and Bob have different total amounts of\u00a0candy.<\/li>\n
  • It is guaranteed there exists an\u00a0answer.<\/li>\n<\/ul>\n
     <\/p>\n
    Solution: HashTable<\/strong><\/h1>\n
    Time complexity: O(A+B)<\/p>\n
    Space complexity: O(B)<\/p>\n
    Clean version<\/p>\n
    \/\/ Author: Huahua\r\n\/\/ Running time: 132 ms\r\nclass Solution {\r\npublic:\r\n  vector<int> fairCandySwap(vector<int>& A, vector<int>& B) {    \r\n    int sum_a = accumulate(begin(A), end(A), 0);\r\n    int sum_b = accumulate(begin(B), end(B), 0);\r\n    unordered_set<int> s(begin(B), end(B));    \r\n    int diff = (sum_b - sum_a) \/ 2;\r\n    for (int a : A)\r\n      if (s.count(a + diff)) return {a, a + diff};\r\n  }\r\n};<\/pre>\n
    Faster version<\/p>\n
    \/\/ Author: Huahua\r\n\/\/ Running time: 68 ms\r\nclass Solution {\r\npublic:\r\n  vector<int> fairCandySwap(vector<int>& A, vector<int>& B) {    \r\n    int sum_a = accumulate(begin(A), end(A), 0);\r\n    int sum_b = 0;\r\n    unordered_set<int> s;\r\n    for (int b : B) {\r\n      sum_b += b;\r\n      s.insert(b);\r\n    }\r\n    int diff = (sum_b - sum_a) \/ 2;\r\n    for (int a : A)\r\n      if (s.count(a + diff)) return {a, a + diff};\r\n  }\r\n};<\/pre>\n
     <\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
    Problem Alice and Bob have candy bars of different sizes:\u00a0A[i]\u00a0is the size of the\u00a0i-th bar of candy that Alice has, and\u00a0B[j]\u00a0is the size of the\u00a0j-th…<\/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":[20,222,384,82],"class_list":["post-3634","post","type-post","status-publish","format-standard","hentry","category-hashtable","tag-array","tag-easy","tag-exchange","tag-hashtable","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/3634","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=3634"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/3634\/revisions"}],"predecessor-version":[{"id":3636,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/3634\/revisions\/3636"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=3634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=3634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=3634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}