4 lines c++ solution.

  • 0
    int numTrees(int n) {
            long long result=1;
            for(int i=n+1;i<=2*n;i++){
                result = (result * i)/(i-n);
            return result/(n+1);

    The total number of possible tree's is given by the formula (2n)!/(n+1)!*n! which is called the Catalan number. Read more about it here.

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