title: Calculating sum 1 to N by adding 1 to N/2 with N/2 to N in a recursive method
body: <p>I am having trouble making a recursive method that calculates the sum of 1,2,3 to N, but does it by adding (1,2,3... to N/2) with (N/2+1... to N).</p>
  
  <p>The code i manage so far is this:</p>
  
  <pre><code>public static void main(String[] args) {
  
      System.out.println(sum(10, 1));
  }
  
  public static int sum(int n, int start) {
  
      if (start == n){
          return n;
      }
  
      if (start &gt; n / 2){
          return start + sum(n, start + 1);
      }
  
      return start + sum(n, start + 1);
  
  }
  </code></pre>
  
  <p>I believe this is wrong, It is an assignment in school where we have to motivate how splitting the recursion up into to parts is a more/lesser efficient way of calculating the sum. (adding numbers from 1 to N/2 with N/2 to N, instead of just from 1 to N directly).</p>
  
  <p>He made us do this way to make it harder for us but i cannot grasp the idea on how to do this at all. Is it correct? </p>
  
  <p>Thanks </p>