{"id":4962,"date":"2019-03-09T22:05:34","date_gmt":"2019-03-10T06:05:34","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=4962"},"modified":"2019-03-09T22:05:56","modified_gmt":"2019-03-10T06:05:56","slug":"1007-minimum-domino-rotations-for-equal-row","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/algorithms\/array\/1007-minimum-domino-rotations-for-equal-row\/","title":{"rendered":"\u82b1\u82b1\u9171 1007. Minimum Domino Rotations For Equal Row"},"content":{"rendered":"\n

In a row of dominoes, A[i]<\/code> and B[i]<\/code> represent the top and bottom halves of the i<\/code>-th domino.  (A domino is a tile with two numbers from 1 to 6 – one on each half of the tile.)<\/p>\n\n\n\n

We may rotate the i<\/code>-th domino, so that A[i]<\/code> and B[i]<\/code> swap values.<\/p>\n\n\n\n

Return the minimum number of rotations so that all the values in A<\/code> are the same, or all the values in B<\/code> are the same.<\/p>\n\n\n\n

If it cannot be done, return -1<\/code>.<\/p>\n\n\n\n

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

\"\"<\/figure>\n\n\n\n
Input: <\/strong>A = [2,1,2,4,2,2], B = [5,2,6,2,3,2]\nOutput: <\/strong>2\nExplanation: <\/strong>\nThe first figure represents the dominoes as given by A and B: before we do any rotations.\nIf we rotate the second and fourth dominoes, we can make every value in the top row equal to 2, as indicated by the second figure.\n<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input: <\/strong>A = [3,5,1,2,3], B = [3,6,3,3,4]\nOutput: <\/strong>-1\nExplanation: <\/strong>\nIn this case, it is not possible to rotate the dominoes to make one row of values equal.\n<\/pre>\n\n\n\n
Note:<\/strong><\/p>\n\n\n\n
  1. 1 <= A[i], B[i] <= 6<\/code><\/li>
  2. 2 <= A.length == B.length <= 20000<\/code><\/li><\/ol>\n\n\n\n
    Solution: Brute Force<\/strong><\/h2>\n\n\n\n
    Time complexity: O(n)
    Space complexity: O(1)<\/p>\n\n\n\n
    \n
    C++<\/h2>\n
    \n\n
    \n\/\/ Author: Huahua, 72 ms, 14.8 MB\nclass Solution {\npublic:\n  int minDominoRotations(vector& A, vector& B) {\n    int ans = INT_MAX;\n    for (int r = 1; r <= 6; ++r) {\n      bool flag = true;\n      int count_a = 0;\n      int count_b = 0;\n      for (int i = 0; i < A.size(); ++i) {\n        if (A[i] != r && B[i] != r) {\n          flag = false; \n          break;\n        }\n        else if (A[i] == r && B[i] == r) continue;\n        else if (A[i] == r) {\n          ++count_a;\n        } else if (B[i] == r) {\n          ++count_b;\n        }\n      }\n      if (flag) ans = min(ans, min(count_a, count_b));\n    }\n    return ans == INT_MAX ? -1 : ans;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    In a row of dominoes, A[i] and B[i] represent the top and bottom halves of the i-th domino.  (A domino is a tile with two numbers from 1 to 6…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[184],"tags":[20,177],"class_list":["post-4962","post","type-post","status-publish","format-standard","hentry","category-array","tag-array","tag-medium","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4962","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=4962"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4962\/revisions"}],"predecessor-version":[{"id":4964,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4962\/revisions\/4964"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=4962"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=4962"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=4962"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}