Number of binary trees possible with n nodes

noOfBinaryTrees

/**
 * Write code to compute number of structural different 
 * binary trees for given 'n' number of nodes. 
 * (with and without Catalan number)
 */

package problems;

public class noOfBinaryTrees {
  public static int noOfTrees(int totalNodes) {
    if(totalNodes <= 1)
      return 1;

    int sum = 0;
		
    for(int i = 1; i <= totalNodes; i++) {
      int leftTree = noOfTrees(i - 1);
      int rightTree = noOfTrees(totalNodes - i);
      sum += (leftTree * rightTree);
    }
		
    return sum;
  }

  // Main to test the code. Better to write JUnit code	
  public static void main(String[] args) {
    System.out.println(noOfTrees(3));
  }
}