search islands 2d array

search_islands.py

def count_islands(input):
    # if there is no input, return 0
    if not input:
        return 0

    # get the size of the array
    row = len(input)
    col = len(input[0])
    count = 0

    #print(row)
    #print(col)

    for i in range(row):
        for j in range(col):
            if input[i][j] == 1:
                dfs(input, row, col, i, j)
                count += 1
    return count

def dfs(input, row, col, x, y):
    if input[x][y] == 0:
        return

    # visited
    input[x][y] = 0

    # check the positions left, right, down and up
    if x != 0:
        dfs(input, row, col, x-1, y)

    if x != row - 1:
        dfs(input, row, col, x+1, y)

    if y != 0:
        dfs(input, row, col, x, y-1)

    if y != col - 1:
        dfs(input, row, col, x, y+1)


input1 = [[1,1,1,1,0],
         [1,1,0,1,0],
         [1,1,0,0,0],
         [0,0,0,0,1]]

print(count_islands(input1))