Count All Valid Pickup and Delivery Options LeetCode solution in C++

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class Solution {
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 public:
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  int countOrders(int n) {
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    int mod = 1e9 + 7;
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    long long ans = 1;
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    for (int i = 1; i <= n; i++) {
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      int m = 2 * i - 1;
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      int p = (m * (m + 1)) / 2;
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      ans = (ans * p) % mod;
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    }
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    return ans;
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  }
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};