每日算法题: Find the Number of Islands

Hi, here's your problem today. This problem was recently asked by LinkedIn:

Given a 2-dimensional grid consisting of 1's (land blocks) and 0's (water blocks), count the number of islands present in the grid. The definition of an island is as follows:
1.) Must be surrounded by water blocks.
2.) Consists of land blocks (1's) connected to adjacent land blocks (either vertically or horizontally).
Assume all edges outside of the grid are water.

Example:
Input:

10001

11000

10110

00000

Output: 3
Here's your starting point:

class Solution(object):

  def inRange(self, grid, r, c):

    numRow, numCol = len(grid), len(grid[0])

    if r < 0 or c < 0 or r >= numRow or c >= numCol:

      return False

    return True



  def numIslands(self, grid):

    # Fill this in.



grid = [[1, 1, 0, 0, 0],

        [0, 1, 0, 0, 1],

        [1, 0, 0, 1, 1],

        [0, 0, 0, 0, 0]]

print(Solution().numIslands(grid))

# 3