{"id":8102,"date":"2021-02-13T20:34:31","date_gmt":"2021-02-14T04:34:31","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=8102"},"modified":"2021-02-13T20:45:51","modified_gmt":"2021-02-14T04:45:51","slug":"leetcode-1758-minimum-changes-to-make-alternating-binary-string","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/string\/leetcode-1758-minimum-changes-to-make-alternating-binary-string\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 1758. Minimum Changes To Make Alternating Binary String"},"content":{"rendered":"\n

You are given a string s<\/code> consisting only of the characters '0'<\/code> and '1'<\/code>. In one operation, you can change any '0'<\/code> to '1'<\/code> or vice versa.<\/p>\n\n\n\n

The string is called alternating if no two adjacent characters are equal. For example, the string \"010\"<\/code> is alternating, while the string \"0100\"<\/code> is not.<\/p>\n\n\n\n

Return the minimum<\/strong> number of operations needed to make<\/em> s<\/code> alternating<\/em>.<\/p>\n\n\n\n

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

Input:<\/strong> s = \"0100\"\nOutput:<\/strong> 1\nExplanation:<\/strong> If you change the last character to '1', s will be \"0101\", which is alternating.\n<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input:<\/strong> s = \"10\"\nOutput:<\/strong> 0\nExplanation:<\/strong> s is already alternating.\n<\/pre>\n\n\n\n
Example 3:<\/strong><\/p>\n\n\n\n
Input:<\/strong> s = \"1111\"\nOutput:<\/strong> 2\nExplanation:<\/strong> You need two operations to reach \"0101\" or \"1010\".\n<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n
  • 1 <= s.length <= 104<\/sup><\/code><\/li>
  • s[i]<\/code> is either '0'<\/code> or '1'<\/code>.<\/li><\/ul>\n\n\n\n
    Solution: Two Counters<\/strong><\/h2>\n\n\n\n
    The final string is either 010101… or 101010…
    We just need two counters to record the number of changes needed to transform the original string to those two final strings.<\/p>\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\nclass Solution {\npublic:\n  int minOperations(string s) {\n    int c1 = 0, c2 = 0;\n    for (int i = 0; i < s.length(); ++i) {\n      c1 += (s[i] - '0' == i % 2);\n      c2 += (s[i] - '0' != i % 2);\n    }\n    return min(c1, c2);\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
    You are given a string s consisting only of the characters ‘0’ and ‘1’. In one operation, you can change any ‘0’ to ‘1’ or vice versa. The string is called alternating if no…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[8,222,4],"class_list":["post-8102","post","type-post","status-publish","format-standard","hentry","category-string","tag-counting","tag-easy","tag-string","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8102","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=8102"}],"version-history":[{"count":2,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8102\/revisions"}],"predecessor-version":[{"id":8104,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/8102\/revisions\/8104"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=8102"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=8102"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=8102"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}