递归-Euler 15

Question

我知道已经发布了针对Euler 15的解决方案。从技术上讲，我已经找到了可行的解决方案（产生正确的数字），但是当它打印出路线时，这样做的方法是错误的

def legal_moves (row, column, grid):
    legal_moves = []
    if row != grid:
        legal_moves.append ([row+1,column])
    if column != grid:
        legal_moves.append ([row,column+1])
    if column == grid and row == grid:
        return False 
    return legal_moves

def find_route (row,column,grid, route):

    l_moves = legal_moves (row,column,grid)
    if l_moves == False:
        route.append ([row,column])
        list_routes.append (route)
        return
    else:
        route.append ([row,column])
        if len(l_moves) == 1:
            row = l_moves[0][0]
            column = l_moves[0][1]
            find_route (row,column,grid,route)
        if len(l_moves) ==2:
            row_a, column_a = l_moves[0][0], l_moves[0][1]
            row_b, column_b = l_moves[1][0], l_moves[1][1]
            find_route (row_a,column_a,grid,route)
            find_route (row_b,column_b,grid,route)

grid = int(input("Enter A for grid size AxA: "))
list_routes = []

find_route(0,0,grid, route = [])
for item in list_routes:
    print (item)
    print ()

我将其用于2号电路板（因此输入：grid = 2）并打印了端子

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

[[0, 0], [1, 0], [2, 0], [2, 1], [2, 2], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 1], [1, 1], [2, 1], [2, 2], [1, 2], [2, 2], [0, 2], [1, 2], [2, 2]]

我无法弄清为什么第1行不仅仅打印：

[0, 0], [1, 0], [2, 0], [2, 1], [2, 2]

和第2行：

[0, 0], [1, 0], [1, 1], [2, 1], [2, 2]

等... 请有人可以帮助我了解原因吗？ 谢谢