Minimum Number of Flips to Make the Binary String Alternating LeetCode solution in C++

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class Solution {
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 public:
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  int minFlips(string s) {
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    int n = s.size();
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    string ss = s + s;
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    string s1, s2;
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    int ans = INT_MAX;
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    for (int i = 0; i < ss.size(); i++) {
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      s1 += (i % 2 ? '1' : '0');
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      s2 += (i % 2 ? '0' : '1');
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    }
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    int ans1 = 0, ans2 = 0;
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    for (int i = 0; i < ss.size(); i++) {
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      if (s1[i] != ss[i]) ans1++;
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      if (s2[i] != ss[i]) ans2++;
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      if (i >= n - 1) {
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        if (i != n - 1 && s1[i - n] != ss[i - n]) ans1--;
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        if (i != n - 1 && s2[i - n] != ss[i - n]) ans2--;
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        ans = min({ans, ans1, ans2});
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      }
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    }
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    return ans;
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  }
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};