CS153/hw6/hw5programs/sp22_tests/binary_tree_tests.oat

struct Node {
 int val;
 Node? left;
   Node? right
}

struct Tuple {
 int max_sum_path;
 int max_path_term_node
}

Node newNode (int val) {
 return new Node {val = val; left = Node null; right = Node null};
}

int getMax(int a, int b) {
 if(a >= b) {
  return a;
 }
 return b;
}

Tuple findMaxSumHelper (Node? root, Tuple input_tuple) {
 
 if?(Node x = root) {

  var l_result = findMaxSumHelper(x.left, input_tuple).max_path_term_node;
  var r_result = findMaxSumHelper(x.right, input_tuple).max_path_term_node;

  var max_children = getMax(l_result, r_result);
  var curr_root_terminating_path = getMax(max_children + x.val, x.val);

  var max_no_parent = getMax(curr_root_terminating_path, x.val + l_result + r_result);

  var res = getMax(input_tuple.max_sum_path, max_no_parent);

  var ret_tuple = new Tuple {max_sum_path = res; max_path_term_node = curr_root_terminating_path};

  return ret_tuple;

 } else {
  var ret = new Tuple {max_sum_path = input_tuple.max_sum_path; max_path_term_node = 0};
  return ret;
 }
}


int findMaxSumDriver(Node root) {
 var input_tuple = new Tuple {max_sum_path = -99999; max_path_term_node = 0};
 var temp = findMaxSumHelper(root, input_tuple);
 return temp.max_sum_path;
}

int program(int argc, string[] argv) {
 var root = newNode(8);
 
 root.left = newNode(2);
 root.right = newNode(70);


 if?(Node r_l = root.left) {
  r_l.left = newNode(50);
  r_l.right = newNode(0);
 }

 if?(Node r_r = root.right) {
  r_r.right = newNode(15);

  if?(Node r_r_r = r_r.right) {
   r_r_r.right = newNode(4);
   r_r_r.left = newNode(-9);
  }
 }
 
 return findMaxSumDriver(root);
}