GCD of Odd and Even Sums — C++

// Time:  O(1)
// Space: O(1)

// math
class Solution {
public:
    int gcdOfOddEvenSums(int n) {
        // gcd((1+(2n-1))*n/2, (2+2n)*n/2) = gcd(n*n, n*(n+1)) = n * gcd(n, n+1) = n
        return n;
    }
};