Sum_Neighbors.ipynb

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   "source": [
    "Write a function that takes in a (x,y) coordinate and a grid and returns the sum \n",
    "of all the neighbors. A neighbor is defined as up/down/left/right/diagonal."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import random"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "def generate_grid(rows, cols):\n",
    "    return [[random.randint(0,9) for i in range(rows)] for j in range(cols)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
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     "name": "stdout",
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     "text": [
      "[2, 4, 6, 1, 4]\n",
      "[1, 6, 4, 2, 8]\n",
      "[6, 9, 1, 3, 8]\n",
      "[6, 2, 8, 1, 8]\n",
      "[8, 7, 9, 9, 7]\n"
     ]
    }
   ],
   "source": [
    "my_grid = generate_grid(5, 5)\n",
    "for row in my_grid:\n",
    "    print(row)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Solution"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "def sum_neighbors(coordinate, grid):\n",
    "    # A neighbor is defined as up/down/left/right/diagonals\n",
    "    neighbors = [(0, -1), (0, 1), (-1, 0), (1, 0), (-1, -1), (-1, 1), (1, -1), (1, 1)]\n",
    "    return sum([find_neighbor(coordinate, grid, neighbor) for neighbor in neighbors])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "def find_neighbor(coordinate, grid, neighbor):\n",
    "    x, y = coordinate[0] + neighbor[0], coordinate[1] + neighbor[1]    \n",
    "    # Don't allow negative indices\n",
    "    if x < 0 or y < 0:\n",
    "        return 0\n",
    "    \n",
    "    try:\n",
    "        return grid[x][y]\n",
    "    except:\n",
    "        return 0"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Tests"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "grid = [\n",
    "    [0, 3, 6, 8, 1],\n",
    "    [2, 7, 5, 0, 3],\n",
    "    [1, 0, 3, 4, 9],\n",
    "    [7, 3, 8, 4, 5],\n",
    "    [2, 3, 9, 5, 7]\n",
    "]\n",
    "\n",
    "test_cases = [\n",
    "    {'coordinate': (0,0), 'expected': 12},\n",
    "    {'coordinate': (1,1), 'expected': 20},\n",
    "    {'coordinate': (2,2), 'expected': 31},\n",
    "    {'coordinate': (3,3), 'expected': 50},\n",
    "    {'coordinate': (4,4), 'expected': 14}\n",
    "]\n",
    "\n",
    "for case in test_cases:\n",
    "    actual = sum_neighbors(case['coordinate'], grid)\n",
    "    expected = case['expected']\n",
    "    assert actual == expected, f\"Actual: {actual} / Expected: {expected}\""
   ]
  }
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