Domino and Tromino Tiling LeetCode solution in C++

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class Solution {
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 public:
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  int numTilings(int n) {
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    long dp[n + 1];
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    dp[0] = 1;
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    for (int i = 1; i <= n; i++) {
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      if (i < 3)
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        dp[i] = i;
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      else
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        dp[i] = (dp[i - 1] * 2 + dp[i - 3]) % 1000000007;
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    }
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    return (int)dp[n];
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  }
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};