{"id":8633,"date":"2021-10-23T20:34:07","date_gmt":"2021-10-24T03:34:07","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=8633"},"modified":"2021-10-23T20:35:49","modified_gmt":"2021-10-24T03:35:49","slug":"leetcode-2022-convert-1d-array-into-2d-array","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/algorithms\/array\/leetcode-2022-convert-1d-array-into-2d-array\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 2022. Convert 1D Array Into 2D Array"},"content":{"rendered":"\n

You are given a 0-indexed<\/strong> 1-dimensional (1D) integer array original<\/code>, and two integers, m<\/code> and n<\/code>. You are tasked with creating a 2-dimensional (2D) array with m<\/code> rows and n<\/code> columns using all<\/strong> the elements from original<\/code>.<\/p>\n\n\n\n

The elements from indices 0<\/code> to n - 1<\/code> (inclusive<\/strong>) of original<\/code> should form the first row of the constructed 2D array, the elements from indices n<\/code> to 2 * n - 1<\/code> (inclusive<\/strong>) should form the second row of the constructed 2D array, and so on.<\/p>\n\n\n\n

Return an <\/em>m x n<\/code> 2D array constructed according to the above procedure, or an empty 2D array if it is impossible<\/em>.<\/p>\n\n\n\n

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

\"\"\/<\/figure>\n\n\n\n
Input:<\/strong> original = [1,2,3,4], m = 2, n = 2\nOutput:<\/strong> [[1,2],[3,4]]\nExplanation:\n<\/strong>The constructed 2D array should contain 2 rows and 2 columns.\nThe first group of n=2 elements in original, [1,2], becomes the first row in the constructed 2D array.\nThe second group of n=2 elements in original, [3,4], becomes the second row in the constructed 2D array.\n<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input:<\/strong> original = [1,2,3], m = 1, n = 3\nOutput:<\/strong> [[1,2,3]]\nExplanation:<\/strong>\nThe constructed 2D array should contain 1 row and 3 columns.\nPut all three elements in original into the first row of the constructed 2D array.\n<\/pre>\n\n\n\n
Example 3:<\/strong><\/p>\n\n\n\n
Input:<\/strong> original = [1,2], m = 1, n = 1\nOutput:<\/strong> []\nExplanation:\n<\/strong>There are 2 elements in original.\nIt is impossible to fit 2 elements in a 1x1 2D array, so return an empty 2D array.\n<\/pre>\n\n\n\n
Example 4:<\/strong><\/p>\n\n\n\n
Input:<\/strong> original = [3], m = 1, n = 2\nOutput:<\/strong> []\nExplanation:<\/strong>\nThere is 1 element in original.\nIt is impossible to make 1 element fill all the spots in a 1x2 2D array, so return an empty 2D array.\n<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n
  • 1 <= original.length <= 5 * 104<\/sup><\/code><\/li>
  • 1 <= original[i] <= 105<\/sup><\/code><\/li>
  • 1 <= m, n <= 4 * 104<\/sup><\/code><\/li><\/ul>\n\n\n\n
    Solution: Brute Force<\/strong><\/h2>\n\n\n\n
    the i-th element in original array will have index (i\/\/n, i % n) in the 2D array.<\/p>\n\n\n\n
    Time complexity: O(n*m)
    Space complexity: O(n*m)<\/p>\n\n\n\n
    \n
    C++<\/h2>\n
    \n\n
    \nclass Solution {\npublic:\n  vector> construct2DArray(vector& original, int m, int n) {\n    if (original.size() != m * n) return {};\n    vector> ans(m, vector(n));\n    for (int i = 0; i < m * n; ++i)\n      ans[i \/ n][i % n] = original[i];\n    return ans;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with m rows and n columns using all the elements from original. The…<\/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":[20,222,216,632],"class_list":["post-8633","post","type-post","status-publish","format-standard","hentry","category-array","tag-array","tag-easy","tag-matrix","tag-row-major","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8633","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=8633"}],"version-history":[{"count":3,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8633\/revisions"}],"predecessor-version":[{"id":8636,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8633\/revisions\/8636"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=8633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=8633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=8633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}