Python“传播”模拟

Question

所以，我有一个格式为

的列表

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

我希望围绕“1”的“0”在一个步骤后变为“1”，就像这样。

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

经过足够多的步骤，所有的“0”都变成了“1”。

我的代码如下

def simulate_bushfire(list, steps):
    for _ in range(steps):# iterates through the number of steps 
        for y in range(len(initial_bushfire[0])):
            for x in range(len(initial_bushfire)): #for all y coordinates possible in the file   
                if initial_bushfire[y][x] =='1':# looks for cells that has '1' in it 
                    for a in range(x-1,x+2): #looks at the neighbour of the cell that has'1' in it (x coordinates)
                        for b in range(y-1,y+2):#looks at the neighbour of the cell that has'1' in it (y coordinates)                           
                            if a<0 or b<0 or b>=len(initial_bushfire[0]) or a>=len(initial_bushfire):# if neighbour is outside the border of the map, 
                                #code will ignore to avoid errors like list out of range 
                                continue
                            if initial_bushfire[b][a]=='':# if there's an empty string (no tree)
                                continue    # ignore this as well (no trees to burn )
                            if initial_bushfire[b][a]=='0': #if there is a '0' in the file (there is a tree)
                                initial_bushfire[b][a]='1'# change the '0' to a '1' (tree on fire)
    return (initial_bushfire)

但对于 1 步来说，“传播”似乎太多了。我似乎无法理解为什么，但我想这是由于这条线

for a in range(x-1,x+2): #looks at the neighbour of the cell that has'1' in it (x coordinates)
    for b in range(y-1,y+2):#looks at the neighbour of the cell that has'1' in it (y coordinates)

如果有人能就这段代码指导我，我将不胜感激。

Answer 1

问题在于，您正在使新蔓延的火成为同一矩阵中原始火的一部分，因此当您继续寻找火时，它们会进一步蔓延到其他灌木丛中。您应该使用单独的列表来跟踪新的火灾，并且仅在完成整个丛林火灾矩阵的扫描后才应用它们：

def simulate_bushfire(initial_bushfire, steps):
    for _ in range(steps):# iterates through the number of steps
        new_fire = []
        for y in range(len(initial_bushfire[0])):
            for x in range(len(initial_bushfire)): #for all y coordinates possible in the file
                if initial_bushfire[y][x] =='1':# looks for cells that has '1' in it
                    for a, b in (x - 1, y), (x + 1, y), (x, y - 1), (x, y + 1): #looks at the neighbouring cells
                        if a<0 or b<0 or b>=len(initial_bushfire[0]) or a>=len(initial_bushfire):# if neighbour is outside the border of the map,
                            #code will ignore to avoid errors like list out of range
                            continue
                        if initial_bushfire[b][a]=='':# if there's an empty string (no tree)
                            continue    # ignore this as well (no trees to burn )
                        if initial_bushfire[b][a]=='0': #if there is a '0' in the file (there is a tree)
                            new_fire.append((b, a))# change the '0' to a '1' (tree on fire)
        for y, x in new_fire:
            initial_bushfire[y][x] = '1'
    return (initial_bushfire)

这样：

simulate_bushfire(l, 1)

会返回：

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