Matrix python函数

Question

我必须写一个函数，在给定一个非空且非负的矩阵的情况下，matrix[i][j]的起始位置(长度为2的非负列表，表示矩阵的位置)将返回最低邻接值的位置(不断前进，直到找到最低的邻接值，只通过其相邻的单元/元素)。

示例:如果matrix = [[8,90,91,73],[60,6,32,84],[50,4,45,94],[12,85,3,2]]和sarting position = [0,0]，则应返回[3,3]。我只想用编程的基础知识(if语句，循环等)来实现这个函数。可以使用像min或max这样的简单助手函数，但请不要太高级。

这就是我到目前为止所做的，但它并不能很好地工作，因为我有索引输出或范围错误：

def search_local_lowest_value(s: List[List[int]], position: List[int]) -> List[int]:
element1 = position[0]
element2 = position[1]
local_variable = s[element1][element2]

while local_variable <= s[row + 1][column] or local_variable <= s[row + 1][column + 1] \
    or local_variable <= s[row + 1][column - 1] or local_variable <= s[row][column + 1] \
    or local_variable <= s[row][column - 1] or local_variable <= s[row -1][column] \
    or local_variable <= s[row - 1][column + 1] or local_varaible <= s[row - 1][column - 1]:
        if local variable <= s[row + 1][column] or local_variable <= s[row + 1][column + 1] \
        or local_variable <= s[row + 1][column - 1] or local_variable <= s[row][column + 1] \
        or local_variable <= s[row][column - 1] or local_variable <= s[row -1][column] \
        or local_variable <= s[row - 1][column + 1] or local_variable <= s[row - 1][column - 1]:
            return min() // don't know what to fill for that
        else: 
            return False

Answer 1

我提出了这个解决方案，我使用了更清晰和干练的方法：

def bordering(start, shape):
  PATTERN = [[-1,-1], [-1, 0], [-1, 1], [0, 0], [0, -1], [0, 1], [1, -1], [1, 0], [1, 1]]
  border = [[start[0] + x, start[1] + y] for x, y in PATTERN]
  valid_border = [item for item in border if item[0] >= 0 and item[1] >= 0 and item[0] <= shape[0] - 1   and item[1] <= shape[1] - 1  ] # removes borders out of the matrix boundaries
  return valid_border

def smaller_from(start, matrix):
  shape = [len(matrix), len(matrix[0])]
  borders = bordering(start, shape)
  minimum = min([ [matrix[x][y], [x,y]] for x,y in borders ]) # maps the values and coordinates in valid borders and returns the minimum
  return minimum

def find_minimum(start, matrix):
  result = []
  while True:
    val_coords = smaller_from(start, matrix)
    result = val_coords
    if val_coords[0] >= matrix[start[0]][start[1]]:
      break
    else:
      start = val_coords[1]
  return result

matrix = [
          [8,90,91,73],
          [60,6,32,84],
          [50,4,45,94],
          [12,85,3,2]]
start = [0, 0]

find_minimum(start, matrix) #=> [2, [3, 3]]