{"id":9617,"date":"2022-04-02T21:46:31","date_gmt":"2022-04-03T04:46:31","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=9617"},"modified":"2022-04-02T21:47:15","modified_gmt":"2022-04-03T04:47:15","slug":"leetcode-2224-minimum-number-of-operations-to-convert-time","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/greedy\/leetcode-2224-minimum-number-of-operations-to-convert-time\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 2224. Minimum Number of Operations to Convert Time"},"content":{"rendered":"\n

You are given two strings current<\/code> and correct<\/code> representing two 24-hour times<\/strong>.<\/p>\n\n\n\n

24-hour times are formatted as \"HH:MM\"<\/code>, where HH<\/code> is between 00<\/code> and 23<\/code>, and MM<\/code> is between 00<\/code> and 59<\/code>. The earliest 24-hour time is 00:00<\/code>, and the latest is 23:59<\/code>.<\/p>\n\n\n\n

In one operation you can increase the time current<\/code> by 1<\/code>, 5<\/code>, 15<\/code>, or 60<\/code> minutes. You can perform this operation any<\/strong> number of times.<\/p>\n\n\n\n

Return the minimum number of operations<\/strong> needed to convert <\/em>current<\/code> to <\/em>correct<\/code>.<\/p>\n\n\n\n

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

Input:<\/strong> current = \"02:30\", correct = \"04:35\"\nOutput:<\/strong> 3\nExplanation:\n<\/strong>We can convert current to correct in 3 operations as follows:\n- Add 60 minutes to current. current becomes \"03:30\".\n- Add 60 minutes to current. current becomes \"04:30\".\n- Add 5 minutes to current. current becomes \"04:35\".\nIt can be proven that it is not possible to convert current to correct in fewer than 3 operations.<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input:<\/strong> current = \"11:00\", correct = \"11:01\"\nOutput:<\/strong> 1\nExplanation:<\/strong> We only have to add one minute to current, so the minimum number of operations needed is 1.\n<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n
  • current<\/code> and correct<\/code> are in the format \"HH:MM\"<\/code><\/li>
  • current <= correct<\/code><\/li><\/ul>\n\n\n\n
    Solution: Greedy<\/strong><\/h2>\n\n\n\n
    Start with 60, then 15, 5 and finally increase 1 minute a time.<\/p>\n\n\n\n
    Time complexity: O(1)
    Space complexity: O(1)<\/p>\n\n\n\n
    \n
    C++<\/h2>\n
    \n\n
    \/\/ Author: Huahua\nclass Solution {\npublic:\n  int convertTime(string current, string correct) {\n    auto getMinute = [](string_view t) {\n      return (t[0] - '0') * 10 * 60 \n             + (t[1] - '0') * 60 \n             + (t[3] - '0') * 10 \n             + (t[4] - '0');\n    };\n    \n    int t1 = getMinute(current);\n    int t2 = getMinute(correct);\n    int ans = 0;    \n    for (int d : {60, 15, 5, 1})\n      while (t2 - t1 >= d) {\n        ++ans;\n        t1 += d;\n      }\n    return ans;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    You are given two strings current and correct representing two 24-hour times. 24-hour times are formatted as “HH:MM”, where HH is between 00 and 23, and MM is between 00 and 59. The earliest 24-hour time is 00:00, and the latest is 23:59.…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[51],"tags":[222,88,4,107],"class_list":["post-9617","post","type-post","status-publish","format-standard","hentry","category-greedy","tag-easy","tag-greedy","tag-string","tag-time","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9617","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=9617"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9617\/revisions"}],"predecessor-version":[{"id":9619,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/9617\/revisions\/9619"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=9617"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=9617"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=9617"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}