Merge pull request #683 from rudradesai200/master

adding catalanNumbers.cpp

Author: iam-abbas

C++/catalanNumbers.cpp

@@ -0,0 +1,21 @@
+#include<iostream>
+#include<assert.h>
+using namespace std;
+
+unsigned long int catalanDP(unsigned int n)
+{
+	unsigned long int catalan[n+1];
+
+	catalan[0] = catalan[1] = 1;
+	for (int i=2; i<=n; i++)
+	{
+		catalan[i] = 0;
+		for (int j=0; j<i; j++)
+			catalan[i] += catalan[j] * catalan[i-j-1];
+	}
+	return catalan[n];
+}
+
+int main(){
+	assert(catalanDP(9) == 4862);
+}