#include <stdio.h>
#include <stdlib.h>
#include <string>
   using namespace std;

const int MAX_VALUE = 1000;

class treenode {
  public:
    int value;
    treenode *left_child;
    treenode *right_child;

    treenode(int v): value(v) {}
};

void print_levels(treenode *root) {
   // YOUR CODE GOES HERE
}

treenode *generate_child(double child_probability, int depth, int max_depth) {
  if (max_depth == depth) return 0;

  treenode *new_node = 0;
  int new_value = random() % MAX_VALUE;
  if ((new_value / (double)MAX_VALUE) < child_probability) {
    new_node = new treenode(random() % MAX_VALUE);
    new_node->left_child = generate_child(child_probability, depth+1, max_depth);
    new_node->right_child = generate_child(child_probability, depth+1, max_depth);
  }
  return new_node;
}

void *print_tree(treenode *root, string indent) {
  if (root == 0) {
    printf("%s----\n", indent.c_str());
  }
  else {
    printf("%s%d\n", indent.c_str(), root->value);
    print_tree(root->left_child, indent + "  ");
    print_tree(root->right_child, indent + "  ");
  } 
}

main(int argc, char **argv) {
  long seed;
  double child_probability;
  int max_depth;

  if (argc != 4) {
    fprintf(stderr, "usage: print_levels seed child_probability max_depth\n");
    exit(1);
  }
  if (sscanf(argv[1], "%ld", &seed) != 1) {
    fprintf(stderr, "seed, %s, must be an integer\n", argv[1]);
    exit(1);
  }

  if (sscanf(argv[2], "%lf", &child_probability) != 1) {
    fprintf(stderr, "child probability, %s, must be a number between 0 and 1\n",
        argv[1]);
    exit(1);
  }
  else if ((child_probability <= 0) || (child_probability >= 1)) {
    fprintf(stderr, "child probability, %s, must be a number between 0 and 1\n",
        argv[1]);
    exit(1);
  }

  if (sscanf(argv[3], "%d", &max_depth) != 1) {
    fprintf(stderr, "max_depth, %s, must be an integer\n", argv[3]);
    exit(1);
  }

  srandom(seed);
  treenode *root = new treenode(random() % MAX_VALUE);
  root->left_child = generate_child(child_probability, 1, max_depth);
  root->right_child = generate_child(child_probability, 1, max_depth);
  print_tree(root, "");
  print_levels(root);
}