July - Day 7 - Island Perimeter

Solution.py

# https://leetcode.com/explore/challenge/card/july-leetcoding-challenge/544/week-1-july-1st-july-7th/3383/

class Solution:
  def islandPerimeter(self, grid: List[List[int]]) -> int:
    def isInvalid(i: int, j: int) -> bool:
      return i < 0 or i >= len(grid) or j < 0 or j >= len(grid[0])
      
    res = 0
    
    for i in range(len(grid)):
      for j in range(len(grid[0])):
        if grid[i][j] == 1:
          for neighbor in [(-1, 0), (0, 1), (1, 0), (0, -1)]:
            if isInvalid(i + neighbor[0], j + neighbor[1]) or \
               grid[i + neighbor[0]][j + neighbor[1]] == 0:
              res += 1
              
    return res