function setup() {
  createCanvas(400, 400);
  background(220);

  let balls = []; // 20 objects
  for (let i = 0; i < 20; i++) {
    // with random position and size (from 10-50)
    // [Your Code Here]
    random_size = random(10, 50);
    balls.push([
      random(0 + random_size / 2, 400 - random_size / 2),
      random(0 + random_size / 2, 400 - random_size / 2),
      random_size,
    ]);
  }

  drawBalls(balls);
  drawBoundingBox(balls);
}

function drawBalls(balls) {
  // [Your Code Here]
  let fill_what = [];
  let num_balls = balls.length;
  for (let i = 0; i < num_balls; i++) {
    fill_what.push("white");
  }

  for (let i = 0; i < num_balls; i++) {
    for (let j = 0; j < num_balls; j++) {
      if (i == j) {
      } else {
        start_x = balls[i][0];
        start_y = balls[i][1];
        end_x = balls[j][0];
        end_y = balls[j][1];

        d_x = end_x - start_x;
        d_y = end_y - start_y;

        distance = (d_x ** 2 + d_y ** 2) ** 0.5;
        temp = balls[i][2] / 2 + balls[j][2] / 2;

        console.log({ i, d_y, distance, temp });

        if (distance < temp) {
          fill_what[i] = "gray";
          fill_what[j] = "gray";
        }
      }
    }
  }

  console.log(fill_what);

  for (let i = 0; i < num_balls; i++) {
    fill(fill_what[i]);
    circle(balls[i][0], balls[i][1], balls[i][2]);
  }
}

// draws smallest rect fitting all balls
function drawBoundingBox(balls) {
  // [Your Code Here]
  box_top = 99999;
  box_left = 9999999;
  box_bottom = -1;
  box_right = -1;

  num_balls = balls.length;
  for (let i = 0; i < num_balls; i++) {
    circle_left = balls[i][0] - balls[i][2] / 2;
    circle_right = balls[i][0] + balls[i][2] / 2;
    circle_top = balls[i][1] - balls[i][2] / 2;
    circle_bottom = balls[i][1] + balls[i][2] / 2;

    box_top = min(box_top, circle_top);
    box_left = min(box_left, circle_left);
    box_bottom = max(box_bottom, circle_bottom);
    box_right = max(box_right, circle_right);
  }

  stroke("red");
  noFill();
  rect(box_left, box_top, box_right - box_left, box_bottom - box_top);
}