Number of Distinct Roll Sequences LeetCode solution in C++

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class Solution {
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 private:
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  int mod = 1e9 + 7;
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  int f(int ind, int prev1, int prev2, int n) {
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    // Base Case
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    if (ind == n) return 1;
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    int ans = 0;
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    for (int i = 1; i <= 6; i++) // Exploring all possible values
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      if (prev1 != i && prev2 != i && (prev1 == 0 || __gcd(prev1, i) == 1))
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        ans = (ans + f(ind + 1, i, prev1, n)) % mod;
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    return ans;
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  }
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 public:
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  int distinctSequences(int n) {
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    return f(0, 0, 0, n);
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  }
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};